Apparatus and method for measuring optical characteristics of teeth

ABSTRACT

Methods for generating optical characteristics data of a dental object, including at least color characteristics, are disclosed. A probe is positioned in proximity to the dental object. The probe provides light to the object and receives light from the object, and the received light is coupled to a video camera, with the object positioned in the field of view of the camera. The optical characteristics data are generated based on camera data corresponding to the object and based on camera data corresponding to a color calibration standard generated with the color calibration standard in the field of view of the camera. The optical characteristics data may be stored in a record of a software database or used to prepare a second dental object.

FIELD OF THE INVENTION

The present invention relates to devices and methods for measuringoptical characteristics such as color of objects such as teeth, and moreparticularly to devices and methods for measuring the color and otheroptical characteristics of teeth or other objects or surfaces with ahand-held probe that presents minimal problems with height or angulardependencies.

BACKGROUND OF THE INVENTION

A need has been recognized for devices and methods of measuring thecolor or other optical characteristics of teeth and other objects in thefield of dentistry. Various color measuring devices such asspectrophotometers and calorimeters are known in the art. To 15understand the limitations of such conventional devices, it is helpfulto understand certain principles relating to color. Without being boundby theory, Applicants provide the following discussion. In thediscussion herein, reference is made to an “object,” etc., and it shouldbe understood that in general such discussion may include teeth as the“object.”

The color of an object determines the manner in which light is reflectedfrom the surface of the object. When light is incident upon an object,the reflected light will vary in intensity and wavelength dependent uponthe color of the surface of the object. Thus, a red object will reflectred light with a greater intensity than a blue or a green object, andcorrespondingly a green object will reflect green light with a greaterintensity than a red or blue object.

One method of quantifying the color of an object is to illuminate itwith broad band spectrum or “white” light, and measure the spectralproperties of the reflected light over the entire visible spectrum andcompare the reflected spectrum with the incident light spectrum. Suchinstruments typically require a broad band spectrophotometer, whichgenerally are expensive, bulky and relatively cumbersome to operate,thereby limiting the practical application of such instruments.

For certain applications, the broad band data provided by aspectrophotometer is unnecessary. For such applications, devices havebeen produced or proposed that quantify color in terms of a numericalvalue or relatively small set of values representative of the color ofthe object.

It is known that the color of an object can be represented by threevalues. For example, the color of an object can be represented by red,green and blue values, an intensity value and color difference values,by a CE value, or by what are known as “tristimulus values” or numerousother orthogonal combinations. It is important that the three values beorthogonal; i.e., any combination of two elements in the set cannot beincluded in the third element.

One such method of quantifying the color of an object is to illuminatean object with broad band “white” light and measure the intensity of thereflected light after it has been passed through narrow band filters.Typically three filters (such as red, green and blue) are used toprovide tristimulus light values representative of the color of thesurface. Yet another method is to illuminate an object with threemonochromatic light sources (such as red, green and blue) one at a timeand then measure the intensity of the reflected light with a singlelight sensor. The three measurements are then converted to a tristimulusvalue representative of the color of the surface. Such color measurementtechniques can be utilized to produce equivalent tristimulus valuesrepresentative of the color of the surface. Generally, it does notmatter if a “white” light source is used with a plurality of colorsensors (or a continuum in the case of a spectrophotometer), or if aplurality of colored light sources are utilized with a single lightsensor.

There are, however, difficulties with the conventional techniques. Whenlight is incident upon a surface and reflected to a light receiver, theheight of the light sensor and the angle of the sensor relative to thesurface and to the light source also affect the intensity of thereceived light. Since the color determination is being made by measuringand quantifying the intensity of the received light for differentcolors, it is important that the height and angular dependency of thelight receiver be eliminated or accounted for in some manner.

One method for eliminating the height and angular dependency of thelight source and receiver is to provide a fixed mounting arrangementwhere the light source and receiver are stationary and the object isalways positioned and measured at a preset height and angle. The fixedmounting arrangement greatly limits the applicability of such a method.Another method is to add mounting feet to the light source and receiverprobe and to touch the object with the probe to maintain a constantheight and angle. The feet in such an apparatus must be wide enoughapart to insure that a constant angle (usually perpendicular) ismaintained relative to the object. Such an apparatus tends to be verydifficult to utilize on small objects or on objects that are hard toreach, and in general does not work satisfactorily in measuring objectswith curved surfaces. Such devices are particularly difficult toimplement in the field of dentistry.

The use of color measuring devices in the field of dentistry has beenproposed. In modern dentistry, the color of teeth typically arequantified by manually comparing a patient's teeth with a set of “shadeguides.” There are numerous shade guides available for dentists in orderto properly select the desired color of dental prosthesis. Such shadeguides have been utilized for decades and the color determination ismade subjectively by the dentist by holding a set of shade guides nextto a patient's teeth and attempting to find the best match.Unfortunately, however, the best match often is affected by the ambientlight color in the dental operatory and the surrounding color of thepatient's makeup or clothing and by the fatigue level of the dentist. Inaddition, such pseudo trial and error methods based on subjectivematching with existing industry shade guides for forming dentalprostheses, fillings and the like often result in unacceptable colormatching, with the result that the prosthesis needs to be remade,leading to increased costs and inconvenience to the patient, dentalprofessional and/or prosthesis manufacturer.

Similar subjective color quantification also is made in the paintindustry by comparing the color of an object with a paint referenceguide. There are numerous paint guides available in the industry and thecolor determination also often is affected by ambient light color, userfatigue and the color sensitivity of the user. Many individuals arecolor insensitive (color blind) to certain colors, further complicatingcolor determination.

While a need has been recognized in the field of dentistry, however, thelimitations of conventional color/optical measuring techniques typicallyrestrict the utility of such techniques. For example, the high cost andbulkiness of typical broad band spectrometers, and the fixed mountingarrangements or feet required to address the height and angulardependency, often limit the applicability of such conventionaltechniques.

Moreover, another limitation of such conventional methods and devicesare that the resolution of the height and angular dependency problemstypically require contact with the object being measured. In certainapplications, it may be desirable to measure and quantify the color ofan object with a small probe that does not require contact with thesurface of the object. In certain applications, for example, hygienicconsiderations make such contact undesirable. In the other applications,contact with the object can mar the surface (such as if the object iscoated in some manner) or otherwise cause undesirable effects.

In summary, there is a need for a low cost, hand-held probe of smallsize that can reliably measure and quantify the color and other opticalcharacteristics of an object without requiring physical contact with theobject, and also a need for methods based on such a device in the fieldof dentistry and other applications.

SUMMARY OF THE INVENTION

In accordance with the present invention, devices and methods areprovided for measuring the color and other optical characteristics ofobjects such as teeth, reliably and with minimal problems of height andangular dependence. A handheld probe is utilized in the presentinvention, with the handheld probe containing a number of fiber opticsin certain preferred embodiments. Light is directed from one (or more)light source(s) towards the object/tooth to be measured, which incertain preferred embodiments is a central light source fiber optic(other light sources and light source arrangements also may beutilized). Light reflected from the object is detected by a number oflight receivers. Included in the light receivers (which may be lightreceiver fiber optics) are a plurality of perimeter receivers (which maybe light receiver fiber optics, etc.). In certain preferred embodiments,three perimeter fiber optics are utilized in order to take measurementsat a desired, and predetermined height and angle, thereby minimizingheight and angular dependency problems found in conventional methods. Incertain embodiments, the present invention also may measure translucenceand fluorescence characteristics of the object/tooth being measured, aswell as surface texture and/or other optical or surface characteristics.

The present invention may include constituent elements of a broad bandspectrophotometer, or, alternatively, may include constituent elementsof a tristimulus type colorimeter. The present invention may employ avariety of color measuring devices in order to measure color in apractical, reliable and efficient manner, and in certain preferredembodiments includes a color filter array and a plurality of colorsensors. A microprocessor is included for control and calculationpurposes. A temperature sensor is included to measure temperature inorder to detect abnormal conditions and/or to compensate for temperatureeffects of the filters or other components of the system. In addition,the present invention may include audio feedback to guide the operatorin making color/optical measurements, as well as one or more displaydevices for displaying control, status or other information.

With the present invention, color/optical measurements of teeth or thelike may be made with a handheld probe in a practical and reliablemanner, essentially free of height and angular dependency problems,without resorting to fixtures, feet or other undesirable mechanicalarrangements for fixing the height and angle of the probe with respectto the object/tooth. In addition, the present invention includes methodsof using such color measurement data to implement processes for formingdental prostheses and the like, as well as methods for keeping suchcolor and/or other data as part of a patient record database.

Accordingly, it is an object of the present invention to addresslimitations of conventional color/optical measuring techniques.

It is another object of the present invention to provide a method anddevice useful in measuring the color or other optical characteristics ofteeth or other objects or surfaces with a hand-held probe of practicalsize that does not require contact with the object or surface.

It is a further object of the present invention to provide acolor/optical measurement probe and method that does not require fixedposition mechanical mounting, feet or other mechanical impediments.

It is yet another object of the present invention to provide a probe andmethod useful for measuring color or other optical characteristics thatmay be utilized with a probe simply placed near the surface to bemeasured.

It is a still further object of the present invention to provide a probeand method that are capable of determining translucency characteristicsof the object being measured.

It is a further object of the present invention to provide a probe andmethod that are capable of determining surface texture characteristicsof the object/tooth being measured.

It is a still further object of the present invention to provide a probeand method that are capable of determining fluorescence characteristicsof the object/tooth being measured.

It is another object of the present invention to provide a probe andmethod that can measure the area of a small spot singulary, or that alsocan measure the color of irregular shapes by moving the probe over anarea and integrating the color of the entire area.

It is a further object of the present invention to provide a method ofmeasuring the color of teeth and preparing dental prostheses, dentures,intraoral tooth-colored fillings or other materials.

It is yet another object of the present invention to provide a methodand apparatus that minimizes contamination problems, while providing areliable and expedient manner in which to measure teeth and preparedental prostheses, dentures, intraoral tooth-colored fillings or othermaterials.

It is an object of the present invention to provide methods of usingmeasured data to implement processes for forming dental prostheses andthe like, as well as methods for keeping such measurement and/or otherdata as part of a patient record database.

It also is an object of the present invention to provide probes andmethods for measuring optical characteristics with a probe that is heldsubstantially stationary with respect to the object or tooth beingmeasured.

Finally, it is an object of the present invention to provide probes andmethods for measuring optical characteristics with a probe that may havea removable tip or shield that may be removed for cleaning, disposedafter use or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more fully understood by a description ofcertain preferred embodiments in conjunction with the attached drawingsin which:

FIG. 1 is a diagram illustrating a preferred embodiment of the presentinvention;

FIG. 2 is a diagram illustrating a cross section of a probe inaccordance with a preferred embodiment of the present invention;

FIG. 3 is a diagram illustrating an arrangement of fiber optic receiversand sensors utilized with a preferred embodiment of the presentinvention;

FIGS. 4A to 4C illustrate certain geometric considerations of fiberoptics;

FIGS. 5A and 5B illustrate the light amplitude received by fiber opticlight receivers as a function of height from an object;

FIG. 6 is a flow chart illustrating a color measuring method inaccordance with an embodiment of the present invention;

FIGS. 7A and 7B illustrate a protective cap that may be used withcertain embodiments of the present invention;

FIGS. 8A and 8B illustrate removable probe tips that may be used withcertain embodiments of the present invention;

FIG. 9 illustrates a fiber optic bundle in accordance with anotherpreferred embodiment of the present invention;

FIGS. 10A, 10B, 10C and 10D illustrate and describe other fiber opticbundle configurations that may be used in accordance with yet otherpreferred embodiments of the present invention;

FIG. 11 illustrates a linear optical sensor array that may be used incertain embodiments of the present invention;

FIG. 12 illustrates a matrix optical sensor array that may be used incertain embodiments of the present invention;

FIGS. 13A and 13B illustrate certain optical properties of a filterarray that may be used in certain embodiments of the present invention;

FIGS. 14A and 14B illustrate examples of received light intensities ofreceivers used in certain embodiments of the present invention;

FIG. 15 is a flow chart illustrating audio tones that may be used incertain preferred embodiments of the present invention;

FIG. 16 is a flow chart illustrating a dental prosthesis manufacturingmethod in accordance with a preferred embodiment of the presentinvention;

FIGS. 17A and 17B illustrate a positioning implement used in certainembodiments of the present invention;

FIG. 18 is a flow chart illustrating a patient database method inaccordance with certain embodiments of the present invention;

FIG. 19 illustrates an integrated unit in accordance with the presentinvention that includes a measuring device and other implements;

FIG. 20 illustrates an embodiment of the present invention, whichutilizes a plurality of rings of light receivers that may be utilized totake measurements with the probe held substantially stationary withrespect to the object being measured;

FIGS. 21 and 22 illustrate an embodiment of the present invention, whichutilizes a mechanical movement and also may be utilized to takemeasurements with the probe held substantially stationary with respectto the object being measured;

FIGS. 23A to 23C illustrate embodiments of the present invention inwhich coherent light conduits may serve as removable probe tips;

FIGS. 24, 25 and 26 illustrate further embodiments of the presentinvention utilizing intraoral reflectometers, intraoral cameras and/orcolor calibration charts in accordance with the present invention; and

FIG. 27 illustrates an embodiment of the present invention in which aninteroral camera and/or other instruments in accordance with the presentinvention may be adapted for use with a dental chair.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in greater detail with referenceto certain preferred embodiments. At various places herein, reference ismade to an “object,” for example. It should be understood that anexemplary use of the present invention is in the field of dentistry, andthus the object typically should be understood to include teeth,dentures, dental-type cements or the like, although for discussionpurposes in certain instances reference is only made to the “object.” Asdescribed elsewhere herein, various refinements and substitutions of thevarious embodiments are possible based on the principles and teachingsherein.

With reference to FIG. 1, an exemplary preferred embodiment of acolor/optical characteristic measuring system and method in accordancewith the present invention will be described. It should be noted that,at various places herein, such a color measuring system is sometimesreferred to as an intraoral reflectometer, etc.

Probe tip 1 encloses a plurality of fiber optics, each of which mayconstitute one or more fiber optic fibers. In a preferred embodiment,the fiber optics contained within probe tip 1 includes a single lightsource fiber optic and three light receiver fiber optics. The use ofsuch fiber optics to measure the color or other optical characteristicsof an object will be described later herein. Probe tip 1 is attached toprobe body 2, on which is fixed switch 17. Switch 17 communicates withmicroprocessor 10 through wire 18 and provides, for example, a mechanismby which an operator may activate the device in order to make acolor/optical measurement. Fiber optics within probe tip 1 terminate atthe forward end thereof (i.e., the end away from probe body 2). Theforward end of probe tip 1 is directed towards the surface of the objectto be measured as described more fully below. The fiber optics withinprobe tip 1 optically extend through probe body 2 and through fiberoptic cable 3 to light sensors 8, which are coupled to microprocessor10.

It should be noted that microprocessor 10 includes conventionalassociated components, such as memory (programmable memory, such asPROM, EPROM or EEPROM; working memory such as DRAMs or SRAMs; and/orother types of memory such as non-volatile memory, such as FLASH),peripheral circuits, clocks and power supplies, although for claritysuch components are not explicitly shown. Other types of computingdevices (such as other microprocessor systems, programmable logic arraysor the like) are used in other embodiments of the present invention.

In the embodiment of FIG. 1, the fiber optics from fiber optic cable 3end at splicing connector 4. From splicing connector 4, each of thethree receiver fiber optics used in this embodiment is spliced into atleast five smaller fiber optics (generally denoted as fibers 7), whichin this embodiment are fibers of equal diameter, but which in otherembodiments may be of unequal diameter (such as a larger or smaller“height/angle” or perimeter fiber, as more fully described herein). Oneof the fibers of each group of five fibers passes to light sensors 8through a neutral density filter (as more fully described with referenceto FIG. 3), and collectively such neutrally filtered fibers are utilizedfor purposes of height/angle determination (and also may be utilized tomeasure surface characteristics, as more fully described herein). Fourof the remaining fibers of each group of fibers passes to light sensors8 through color filters and are used to make the color/opticalmeasurement. In still other embodiments, splicing connector 4 is notused, and fiber bundles of, for example, five or more fibers each extendfrom light sensors 8 to the forward end of probe tip 1. In certainembodiments, unused fibers or other materials may be included as part ofa bundle of fibers for purposes of, for example, easing themanufacturing process for the fiber bundle. What should be noted isthat, for purposes of the present invention, a plurality of lightreceiver fiber optics or elements (such as fibers 7) are presented tolight sensors 8, with the light from the light receiver fiberoptics/elements representing light reflected from object 20. While thevarious embodiments described herein present tradeoffs and benefits thatmay not have been apparent prior to the present invention (and thus maybe independently novel), what is important for the present discussion isthat light from fiber optics/elements at the forward end of probe tip 1is presented to sensors 8 for color/optical measurements andangle/height determination, etc.

Light source 11 in the preferred embodiment is a halogen light source(of, for example, 5-100 watts, with the particular wattage chosen forthe particular application), which may be under the control ofmicroprocessor 10. The light from light source 11 reflects from coldmirror 6 and into source fiber optic 5. Source fiber optic 5 passesthrough to the forward end of probe tip 1 and provides the lightstimulus used for purposes of making the measurements described herein.Cold mirror 6 reflects visible light and passes infra-red light, and isused to reduce the amount of infra-red light produced by light source 11before the light is introduced into source fiber optic 5. Such infra-redlight reduction of the light from a halogen source such as light source11 can help prevent saturation of the receiving light sensors, which canreduce overall system sensitivity. Fiber 15 receives light directly fromlight source 11 and passes through to light sensors 8 (which may bethrough a neutral density filter). Microprocessor 10 monitors the lightoutput of light source 11 through fiber 15, and thus may monitor and, ifnecessary compensate for, drift of the output of light source 11. Incertain embodiments, microprocessor 10 also may sound an alarm (such asthrough speaker 16) or otherwise provide some indication if abnormal orother undesired performance of light source 11 is detected.

The data output from light sensors 8 pass to microprocessor 10.Microprocessor 10 processes the data from light sensors 8 to produce ameasurement of color and/or other characteristics. Microprocessor 10also is coupled to key pad switches 12, which serve as an input device.Through key pad switches 12, the operator may input control informationor commands, or information relating to the object being measured or thelike. In general, key pad switches 12, or other suitable data inputdevices (such as push button, toggle, membrane or other switches or thelike), serve as a mechanism to input desired information tomicroprocessor 10.

Microprocessor 10 also communicates with UART 13, which enablesmicroprocessor 10 to be coupled to an external device such as computer13A. In such embodiments, data provided by microprocessor 10 may beprocessed as desired for the particular application, such as foraveraging, format conversion or for various display or print options,etc. In the preferred embodiment, UART 13 is configured so as to providewhat is known as a RS232 interface, such as is commonly found inpersonal computers.

Microprocessor 10 also communicates with LCD 14 for purposes ofdisplaying status, control or other information as desired for theparticular application. For example, color bars, charts or other graphicrepresentations of the color or other collected data and/or the measuredobject or tooth may be displayed. In other embodiments, other displaydevices are used, such as CRTs, matrix-type LEDs, lights or othermechanisms for producing a visible indicia of system status or the like.Upon system initialization, for example, LCD 14 may provide anindication that the system is stable, ready and available for takingcolor measurements.

Also coupled to microprocessor 10 is speaker 16. Speaker 16, in apreferred embodiment as discussed more fully below, serves to provideaudio feedback to the operator, which may serve to guide the operator inthe use of the device. Speaker 16 also may serve to provide status orother information alerting the operator of the condition of the system,including an audio tone, beeps or other audible indication (i.e., voice)that the system is initialized and available for taking measurements.Speaker 16 also may present audio information indicative of the measureddata, shade guide or reference values corresponding to the measureddata, or an indication of the status of the color/optical measurements.

Microprocessor 10 also receives an input from temperature sensor 9.Given that many types of filters (and perhaps light sources or othercomponents) may operate reliably only in a given temperature range,temperature sensor 9 serves to provide temperature information tomicroprocessor 10. In particular, color filters, such as may be includedin light sensors 8, may be sensitive to temperature, and may operatereliably only over a certain temperature range. In certain embodiments,if the temperature is within a usable range, microprocessor 10 maycompensate for temperature variations of the color filters. In suchembodiments, the color filters are characterized as to filteringcharacteristics as a function of temperature, either by data provided bythe filter manufacturer, or through measurement as a function oftemperature. Such filter temperature compensation data may be stored inthe form of a look-up table in memory, or may be stored as a set ofpolynomial coefficients from which the temperature characteristics ofthe filters may be computed by microprocessor 10.

In general, under control of microprocessor 10, which may be in responseto operator activation (through, for example, key pad switches 12 orswitch 17), light is directed from light source 11, and reflected fromcold mirror 6 through source fiber optic 5 (and through fiber opticcable 3, probe body 2 and probe tip 1) or through some other suitablelight source element and is directed onto object 20. Light reflectedfrom object 20 passes through the receiver fiber optics/elements inprobe tip 1 to light sensors 8 (through probe body 2, fiber optic cable3 and fibers 7). Based on the information produced by light sensors 8,microprocessor 10 produces a color/optical measurement result or otherinformation to the operator. Color measurement or other data produced bymicroprocessor 10 may be displayed on display 14, passed through UART 13to computer 13A, or used to generate audio information that is presentedto speaker 16. Other operational aspects of the preferred embodimentillustrated in FIG. 1 will be explained hereinafter.

With reference to FIG. 2, a preferred embodiment of a fiber opticarrangement presented at the forward end of probe tip 1 will now bedescribed. As illustrated in FIG. 2, a preferred embodiment of thepresent invention utilizes a single central light source fiber optic,denoted as light source fiber optic S, and a plurality of perimeterlight receiver fiber optics, denoted as light receivers R1, R2 and R3.As is illustrated, a preferred embodiment of the present inventionutilizes three perimeter fiber optics, although in other embodimentstwo, four or some other number of receiver fiber optics are utilized. Asmore fully described herein, the perimeter light receiver fiber opticsserve not only to provide reflected light for purposes of making thecolor/optical measurement, but such perimeter fibers also serve toprovide information regarding the angle and height of probe tip 1 withrespect to the surface of the object that is being measured, and alsomay provide information regarding the surface characteristics of theobject that is being measured.

In the illustrated preferred embodiment, receiver fiber optics R1 to R3are positioned symmetrically around source fiber optic S, with a spacingof about 120 degrees from each other. It should be noted that spacing tis provided between receiver fiber optics R1 to R3 and source fiberoptic S. While the precise angular placement of the receiver fiberoptics around the perimeter of the fiber bundle in general is notcritical, it has been determined that three receiver fiber opticspositioned 120 degrees apart generally may give acceptable results. Asdiscussed above, in certain embodiments light receiver fiber optics R1to R3 each constitute a single fiber, which is divided at splicingconnector 4 (refer again to FIG. 1), or, in alternate embodiments, lightreceiver fiber optics R1 to R3 each constitute a bundle of fibers,numbering, for example, at least five fibers per bundle. It has beendetermined that, with available fibers of uniform size, a bundle of, forexample, seven fibers may be readily produced (although as will beapparent to one of skill in the art, the precise number of fibers may bedetermined in view of the desired number of receiver fiber optics,manufacturing considerations, etc.). The use of light receiver fiberoptics R1 to R3 to produce color/optical measurements in accordance withthe present invention is further described elsewhere herein, although itmay be noted here that receiver fiber optics R1 to R3 may serve todetect whether, for example, the angle of probe tip 1 with respect tothe surface of the object being measured is at 90 degrees, or if thesurface of the object being measured contains surface texture and/orspectral irregularities. In the case where probe tip 1 is perpendicularto the surface of the object being measured and the surface of theobject being measured is a diffuse reflector (i.e., a matte-typereflector, as compared to a spectral or shiny-type reflector which mayhave “hot spots”), then the light intensity input into the perimeterfibers should be approximately equal. It also should be noted thatspacing t serves to adjust the optimal height at which color/opticalmeasurements should be made (as more fully described below).

In one particular aspect of the present invention, area between thefiber optics on probe tip 1 may be wholly or partially filled with anon-reflective material and/or surface (which may be a black mat,contoured or other non-reflective surface). Having such exposed area ofprobe tip 1 non-reflective helps to reduce undesired reflections,thereby helping to increase the accuracy and reliability of the presentinvention.

With reference to FIG. 3, a partial arrangement of light receiver fiberoptics and sensors used in a preferred embodiment of the presentinvention will now be described. Fibers 7 represent light receivingfiber optics, which transmit light reflected from the object beingmeasured to light sensors 8. In a preferred embodiment, sixteen sensors(two sets of eight) are utilized, although for ease of discussion only 8are illustrated in FIG. 3 (in this preferred embodiment, the circuitryof FIG. 3 is duplicated, for example, in order to result in sixteensensors). In other embodiments, other numbers of sensors are utilized inaccordance with the present invention.

Light from fibers 7 is presented to sensors 8, which in a preferredembodiment pass through filters 22 to sensing elements 24. In thispreferred embodiment, sensing elements 24 include light-to-frequencyconverters, manufactured by Texas Instruments and sold under the partnumber TSL230. Such converters constitute, in general, photo diodearrays that integrate the light received from fibers 7 and output an ACsignal with a frequency proportional to the intensity (not frequency) ofthe incident light. Without being bound by theory, the basic principleof such devices is that, as the intensity increases, the integratoroutput voltage rises more quickly, and the shorter the integrator risetime, the greater the output frequency. The outputs of the TSL230sensors are TTL or CMOS compatible digital signals, which may be coupledto various digital logic devices.

The outputs of sensing elements 24 are, in this embodiment, asynchronoussignals of frequencies depending upon the light intensity presented tothe particular sensing elements, which are presented to processor 26. Ina preferred embodiment, processor 26 is a Microchip PIC16C55 or PIC16C57microprocessor, which as described more fully herein implements analgorithm to measure the frequencies of the signals output by sensingelements 24. In other embodiments, a more integratedmicroprocessor/microcontroller, such as Hitachi's SH RISCmicrocontrollers, is utilized to provide further system integration orthe like.

As previously described, processor 26 measures the frequencies of thesignals output from sensing elements 24. In a preferred embodiment,processor 26 implements a software timing loop, and at periodicintervals processor 26 reads the states of the outputs of sensingelements 24. An internal counter is incremented each pass through thesoftware timing loop. The accuracy of the timing loop generally isdetermined by the crystal oscillator time base (not shown in FIG. 3)coupled to processor 26 (such oscillators typically are quite stable).After reading the outputs of sensing elements 24, processor 26 performsan exclusive OR (“XOR”) operation with the last data read (in apreferred embodiment such data is read in byte length). If any bit haschanged, the XOR operation will produce a 1, and, if no bits havechanged, the XOR operation will produce a 0. If the result is non-zero,the input byte is saved along with the value of the internal counter(that is incremented each pass through the software timing loop). If theresult is zero, the systems waits (e.g., executes no operationinstructions) the same amount of time as if the data had to be saved,and the looping operation continues. The process continues until alleight inputs have changed at least twice, which enables measurement of afull ½ period of each input. Upon conclusion of the looping process,processor 26 analyzes the stored input bytes and internal counterstates. There should be 2 to 16 saved inputs (for the 8 total sensors ofFIG. 3) and counter states (if two or more inputs change at the sametime, they are saved simultaneously). As will be understood by one ofskill in the art, the stored values of the internal counter containsinformation determinative of the period of the signals received fromsensing elements 24. By proper subtraction of internal counter values attimes when an input bit has changed, the period may be calculated. Suchperiods calculated for each of the outputs of sensing elements isprovided by processor 26 to microprocessor 10 (see, e.g., FIG. 1). Fromsuch calculated periods, a measure of the received light intensities maybe calculated.

It should be noted that the sensing circuitry and methodologyillustrated in FIG. 3 have been determined to provide a practical andexpedient manner in which to measure the light intensities received bysensing elements 24. In other embodiments, other circuits andmethodologies are employed (other exemplary sensing schemes aredescribed elsewhere herein).

As discussed above with reference to FIG. 1, one of fibers 7 measureslight source 11, which may be through a neutral density filter, whichserves to reduce the intensity of the received light in order maintainthe intensity roughly in the range of the other received lightintensities. Three of fibers 7 also are from perimeter receiver fiberoptics R1 to R3 (see, e.g., FIG. 2) and also may pass through neutraldensity filters. Such receiving fibers 7 serve to provide data fromwhich angle/height information and/or surface characteristics may bedetermined.

The remaining twelve fibers (of the preferred embodiment's total of 16fibers) of fibers 7 pass through color filters and are used to producethe color measurement. In a preferred embodiment, the color filters areKodak Sharp Cutting Wratten Gelatin Filters, which pass light withwavelengths greater than the cut-off value of the filter (i.e., redishvalues), and absorb light with wavelengths less than the cut-off valueof the filter (i.e., bluish values). “Sharp Cutting” filters areavailable in a wide variety of cut-off frequencies/wavelengths, and thecut-off values generally may be selected by proper selection of thedesired cut-off filter. In a preferred embodiment, the filter cut-offvalues are chosen to cover the entire visible spectrum and, in general,to have band spacings of approximately the visible band range (or otherdesired range) divided by the number of receivers/filters. As anexample, 700 nanometers minus 400 nanometers, divided by 11 bands(produced by twelve color receivers/sensors), is roughly 30 nanometerband spacing.

With an array of cut-off filters as described above, and without beingbound by theory or the specific embodiments described herein, thereceived optical spectrum may be measured/calculated by subtracting thelight intensities of “adjacent” color receivers. For example, band 1(400 nm to 430 nm)=(intensity of receiver 12) minus (intensity ofreceiver 11), and so on for the remaining bands. Such an array ofcut-off filters, and the intensity values that may result from filteringwith such an array, are more fully described in connection with FIGS.13A to 14B.

It should be noted here that in alternate embodiments other color filterarrangements are utilized. For example, “notch” or bandpass filters maybe utilized, such as may be developed using Schott glass-type filters(whether constructed from separate longpass/shortpass filters orotherwise).

In a preferred embodiment of the present invention, the specificcharacteristics of the light source, filters, sensors and fiber optics,etc., are normalized/calibrated by directing the probe towards, andmeasuring, a known color standard. Such normalization/calibration may beperformed by placing the probe in a suitable fixture, with the probedirected from a predetermined position (i.e., height and angle) from theknown color standard. Such measured normalization/calibration data maybe stored, for example, in a look-up table, and used by microprocessor10 to normalize or correct measured color or other data. Such proceduresmay be conducted at start-up, at regular periodic intervals, or byoperator command, etc.

What should be noted from the above description is that the receivingand sensing fiber optics and circuitry illustrated in FIG. 3 provide apractical and expedient way to determine the color by measuring theintensity of the light reflected from the surface of the object beingmeasured.

It also should be noted that such a system measures the spectral band ofthe reflected light from the object, and once measured such spectraldata may be utilized in a variety of ways. For example, such spectraldata may be displayed directly as intensity-wavelength band values. Inaddition, tristimulus type values may be readily computed (through, forexample, conventional matrix math), as may any other desired colorvalues. In one particular embodiment useful in dental applications (suchas for dental prostheses), the color data is output in the form of aclosest match or matches of dental shade guide value(s). In a preferredembodiment, various existing shade guides (such as the shade guidesproduced by Vita Zahnfabrik) are characterized and stored in a look-uptable, or in the graphics art industry Pantone color references, and thecolor measurement data are used to select the closest shade guide valueor values, which may be accompanied by a confidence level or othersuitable factor indicating the degree of closeness of the match ormatches, including, for example, what are known as ΔE values or rangesof ΔE values, or criteria based on standard deviations, such as standarddeviation minimization. In still other embodiments, the colormeasurement data are used (such as with look-up tables) to selectmaterials for the composition of paint or ceramics such as forprosthetic teeth. There are many other uses of such spectral datameasured in accordance with the present invention.

It is known that certain objects such as human teeth may fluoresce, andsuch optical characteristics also may be measured in accordance with thepresent invention. A light source with an ultraviolet component may beused to produce more accurate color/optical data with respect to suchobjects. In certain embodiments, a tungsten/halogen source (such as usedin a preferred embodiment) may be combined with a UV light source (suchas a mercury vapor, xenon or other fluorescent light source, etc.) toproduce a light output capable of causing the object to fluoresce.Alternately, a separate UV light source, combined with avisible-light-blocking filter, may be used to illuminate the object.Such a UV light source may be combined with light from a red LED (forexample) in order to provide a visual indication of when the UV light ison and also to serve as an aid for the directional positioning of theprobe operating with such a light source. A second measurement may betaken using the UV light source in a manner analogous to that describedearlier, with the band of the red LED or other supplemental light sourcebeing ignored. The second measurement may thus be used to produce anindication of the fluorescence of the tooth or other object beingmeasured. With such a UV light source, a silica fiber optic (or othersuitable material) typically would be required to transmit the light tothe object (standard fiber optic materials such as glass and plastic ingeneral do not propagate UV light in a desired manner, etc.).

As described earlier, in certain preferred embodiments the presentinvention utilizes a plurality of perimeter receiver fiber optics spacedapart from and around a central source fiber optic to measure color anddetermine information regarding the height and angle of the probe withrespect to the surface of the object being measured, which may includeother surface characteristic information, etc. Without being bound bytheory, certain principles underlying this aspect of the presentinvention will now be described with reference to FIGS. 4A to 4C.

FIG. 4A illustrates a typical step index fiber optic consisting of acore and a cladding. For this discussion, it is assumed that the corehas an index of refraction of no and the cladding has an index ofrefraction of n₁. Although the following discussion is directed to “stepindex” fibers, it will be appreciated by those of skill in the art thatsuch discussion generally is applicable for gradient index fibers aswell.

In order to propagate light without loss, the light must be incidentwithin the core of the fiber optic at an angle greater than the criticalangle, which may be represented as Sin⁻ {n₁/n₀}, where no is the indexof refraction of the core and n, is the index of refraction of thecladding. Thus, all light must enter the fiber at an acceptance angleequal to or less than phi, with phi=2×Sin⁻¹{(n₀ ²−n₁ ²)}, or it will notbe propagated in a desired manner.

For light entering a fiber optic, it must enter within the acceptanceangle phi. Similarly, when the light exits a fiber optic, it will exitthe fiber optic within a cone of angle phi as illustrated in FIG. 4A.The value (n₀ ²−n₁ ²) is referred to as the aperture of the fiber optic.For example, a typical fiber optic may have an aperture of 0.5, and anacceptance angle of 60°.

Consider using a fiber optic as a light source. One end is illuminatedby a light source (such as light source 11 of FIG. 1), and the other isheld near a surface. The fiber optic will emit a cone of light asillustrated in FIG. 4A. If the fiber optic is held perpendicular to asurface it will create a circular light pattern on the surface. As thefiber optic is raised, the radius r of the circle will increase. As thefiber optic is lowered, the radius of the light pattern will decrease.Thus, the intensity of the light (light energy per unit area) in theilluminated circular area will increase as the fiber optic is loweredand will decrease as the fiber optic is raised.

The same principle generally is true for a fiber optic being utilized asa receiver. Consider mounting a light sensor on one end of a fiber opticand holding the other end near an illuminated surface. The fiber opticcan only propagate light without loss when the light entering the fiberoptic is incident on the end of the fiber optic near the surface if thelight enters the fiber optic within its acceptance angle phi. A fiberoptic utilized as a light receiver near a surface will only accept andpropagate light from the circular area of radius r on the surface. Asthe fiber optic is raised from the surface, the area increases. As thefiber optic is lowered to the surface, the area decreases.

Consider two fiber optics parallel to each other as illustrated in FIG.4B. For simplicity of discussion, the two fiber optics illustrated areidentical in size and aperture. The following discussion, however,generally would be applicable for fiber optics that differ in size andaperture. One fiber optic is a source fiber optic, the other fiber opticis a receiver fiber optic. As the two fiber optics are heldperpendicular to a surface, the source fiber optic emits a cone of lightthat illuminates a circular area of radius r. The receiver fiber opticcan only accept light that is within its acceptance angle phi, or onlylight that is received within a cone of angle phi. If the only lightavailable is that emitted by the source fiber optic, then the only lightthat can be accepted by the receiver fiber optic is the light thatstrikes the surface at the intersection of the two circles asillustrated in FIG. 4C. As the two fiber optics are lifted from thesurface, the proportion of the intersection of the two circular areasrelative to the circular area of the source fiber optic increases. Asthey near the surface, the proportion of the intersection of the twocircular areas to the circular area of the source fiber optic decreases.If the fiber optics are held too close to the surface, the circularareas will no longer intersect and no light emitted from the sourcefiber optic will be received by the receiver fiber optic.

As discussed earlier, the intensity of the light in the circular areailluminated by the source fiber increases as the fiber is lowered to thesurface. The intersection of the two cones, however, decreases as thefiber optic pair is lowered. Thus, as the fiber optic pair is lowered toa surface, the total intensity of light received by the receiver fiberoptic increases to a maximal value, and then decreases sharply as thefiber optic pair is lowered still further to the surface. Eventually,the intensity will decrease essentially to zero (assuming the objectbeing measured is not translucent, as described more fully herein), andwill remain essentially zero until the fiber optic pair is in contactwith the surface. Thus, as a source-receiver pair of fiber optics asdescribed above are positioned near a surface and as their height isvaried, the intensity of light received by the receiver fiber opticreaches a maximal value at a peaking or “critical height” h_(c).

Again without being bound by theory, an interesting property of thecritical height h_(c) has been observed. The critical height h_(c) is afunction primarily of the geometry of fixed parameters, such as fiberapertures, fiber diameters and fiber spacing. Since the receiver fiberoptic in the illustrated arrangement is only detecting a maximum valueand not attempting to quantify the value, its maximum in general isindependent of the surface characteristics. It is only necessary thatthe surface reflect sufficient light from the intersecting area of thesource and receiver fiber optics to be within the detection range of thereceiver fiber optic light sensor. Thus, in general red or green or blueor any color surface will all exhibit a maximum at the same criticalheight h_(c). Similarly, smooth reflecting surfaces and rough surfacesalso will have varying intensity values at the maximal value, butgenerally speaking all such surfaces will exhibit a maximum at the samecritical height h_(c). The actual value of the light intensity will be afunction of the color of the surface and of the surface characteristics,but the height where the maximum intensity value occurs in general willnot. This is particularly true with respect to similar types orcategories of materials, such as teeth, industrial objects, etc.

Although the above discussion has focused on two fiber opticsperpendicular to a surface, similar analysis is applicable for fiberoptic pairs at other angles. When a fiber optic is not perpendicular toa surface, it generally illuminates an elliptical area. Similarly, theacceptance area of a receiver fiber optic generally becomes elliptical.As the fiber optic pair is moved closer to the surface, the receiverfiber optic also will detect a maximal value at a critical heightindependent of the surface color or characteristics. The maximalintensity value measured when the fiber optic pair is not perpendicularto the surface, however, will be less than the maximal intensity valuemeasured when the fiber optic pair is perpendicular to the surface.

Referring now to FIGS. 5A and 5B, the intensity of light received as afiber optic source-receiver pair is moved to and from a surface will nowbe described. FIG. 5A illustrates the intensity of the received light asa function of time. Corresponding FIG. 5B illustrates the height of thefiber optic pair from the surface of the object being measured. FIGS. 5Aand 5B illustrate (for ease of discussion) a relatively uniform rate ofmotion of the fiber optic pair to and from the surface of the objectbeing measured (although similar illustrations/analysis would beapplicable for non-uniform rates as well).

FIG. 5A illustrates the intensity of received light as the fiber opticpair is moved to and then from a surface. While FIG. 5A illustrates theintensity relationship for a single receiver fiber optic, similarintensity relationships would be expected to be observed for otherreceiver fiber optics, such as, for example, the multiple receiver fiberoptics of FIGS. 1 and 2. In general with the preferred embodimentdescribed above, all fifteen fiber optic receivers (of fibers 7) willexhibit curves similar to that illustrated in FIG. 5A.

FIG. 5A illustrates five regions. In region 1, the probe is movedtowards the surface of the object being measured, which causes thereceived light intensity to increase. In region 2, the probe is movedpast the critical height, and the received light intensity peaks andthen falls off sharply. In region 3, the probe essentially is in contactwith the surface of the object being measured. As illustrated, thereceived intensity in region 3 will vary depending upon the translucenceof the object being measured. If the object is opaque, the receivedlight intensity will be very low, or almost zero (perhaps out of rangeof the sensing circuitry). If the object is translucent, however, thelight intensity will be quite high, but in general should be less thanthe peak value. In region 4, the probe is lifted and the light intensityrises sharply to a maximum value. In region 5, the probe is liftedfurther away from the object, and the light intensity decreases again.

As illustrated, two peak intensity values (discussed as P1 and P2 below)should be detected as the fiber optic pair moves to and from the objectat the critical height h_(c). If peaks P1 and P2 produced by a receiverfiber optic are the same value, this generally is an indication that theprobe has been moved to and from the surface of the object to bemeasured in a consistent manner. If peaks P1 and P2 are of differentvalues, then these may be an indication that the probe was not moved toand from the surface of the object in a desired manner, or that thesurface is curved or textured, as described more fully herein. In such acase, the data may be considered suspect and rejected. In addition,peaks P1 and P2 for each of the perimeter fiber optics (see, e.g., FIG.2) should occur at the same critical height (assuming the geometricattributes of the perimeter fiber optics, such as aperture, diameter andspacing from the source fiber optic, etc.). Thus, the perimeter fiberoptics of a probe moved in a consistent, perpendicular manner to andfrom the surface of the object being measured should have peaks P1 andP2 that occur at the same critical height. Monitoring receiver fibersfrom the perimeter receiver fiber optics and looking for simultaneous(or near simultaneous, e.g., within a predetermined range) peaks P1 andP2 provides a mechanism for determining if the probe is held at adesired perpendicular angle with respect to the object being measured.

In addition, the relative intensity level in region 3 serves as anindication of the level of translucency of the object being measured.Again, such principles generally are applicable to the totality ofreceiver fiber optics in the probe (see, e.g., fibers 7 of FIGS. 1 and3). Based on such principles, measurement techniques in accordance withthe present invention will now be described.

FIG. 6 is a flow chart illustrating a measuring technique in accordancewith the present invention. Step 49 indicates the start or beginning ofa color/optical measurement. During step 49, any equipmentinitialization, diagnostic or setup procedures may be performed. Audioor visual information or other indicia may be given to the operator toinform the operator that the system is available and ready to take ameasurement. Initiation of the color/optical measurement commences bythe operator moving the probe towards the object to be measured, and maybe accompanied by, for example, activation of switch 17 (see FIG. 1).

In step 50, the system on a continuing basis monitors the intensitylevels for the receiver fiber optics (see, e.g., fibers 7 of FIG. 1). Ifthe intensity is rising, step 50 is repeated until a peak is detected.If a peak is detected, the process proceeds to step 52. In step 52,measured peak intensity P1, and the time at which such peak occurred,are stored in memory (such as in memory included as a part ofmicroprocessor 10), and the process proceeds to step 54. In step 54, thesystem continues to monitor the intensity levels of the receiver fiberoptics. If the intensity is falling, step 54 is repeated. If a “valley”or plateau is detected (i.e., the intensity is no longer falling, whichgenerally indicates contact or near contact with the object), then theprocess proceeds to step 56. In step 56, the measured surface intensity(IS) is stored in memory, and the process proceeds to step 58. In step58, the system continues to monitor the intensity levels of the receiverfibers. If the intensity is rising, step 58 is repeated until a peak isdetected. If a peak is detected, the process proceeds to step 60. Instep 60, measured peak intensity P2, and the time at which such peakoccurred, are stored in memory, and the process proceeds to step 62. Instep 62, the system continues to monitor the intensity levels of thereceiver fiber optics. Once the received intensity levels begin to fallfrom peak P2, the system perceives that region 5 has been entered (see,e.g., FIG. 5A), and the process proceeds to step 64.

In step 64, the system, under control of microprocessor 10, may analyzethe collected data taken by the sensing circuitry for the variousreceiver fiber optics. In step 64, peaks P1 and P2 of one or more of thevarious fiber optics may be compared. If any of peaks P1 and P2 for anyof the various receiver fiber optics have unequal peak values, then thedata may be rejected, and the entire color measuring process repeated.Again, unequal values of peaks P1 and P2 may be indicative, for example,that the probe was moved in a non-perpendicular or otherwise unstablemanner (i.e., angular or lateral movement), and, for example, peak P1may be representative of a first point on the object, while peak P2 maybe representative of a second point on the object. As the data issuspect, in a preferred embodiment of the present invention, data takenin such circumstances are rejected in step 64.

If the data are not rejected in step 64, the process proceeds to step66. In step 66, the system analyzes the data taken from theneutral-density-filtered receivers from each of the perimeter fiberoptics (e.g., R1 to R3 of FIG. 2). If the peaks of the perimeter fiberoptics did not occur at or about the same point in time, this may beindicative, for example, that the probe was not held perpendicular tothe surface of the object being measured. As nonperpendicular alignmentof the probe with the surface of the object being measured may causesuspect results, in a preferred embodiment of the present invention,data taken in such circumstances are rejected in step 66. In onepreferred embodiment, detection of simultaneous or near simultaneouspeaking (peaking within a predetermined range of time) serves as anacceptance criterion for the data, as perpendicular alignment generallyis indicated by simultaneous or near simultaneous peaking of theperimeter fiber optics. In other embodiments, step 66 includes ananalysis of peak values P1 and P2 of the perimeter fiber optics. In suchembodiments, the system seeks to determine if the peak values of theperimeter fiber optics (perhaps normalized with any initial calibrationdata) are equal within a defined range. If the peak values of theperimeter fiber optics are within the defined range, the data may beaccepted, and if not, the data may be rejected. In still otherembodiments, a combination of simultaneous peaking and equal valuedetection are used as acceptance/rejection criteria for the data, and/orthe operator may have the ability (such as through key pad switches 12)to control one or more of the acceptance criteria ranges. With suchcapability, the sensitivity of the system may be controllably altered bythe operator depending upon the particular application and operativeenvironment, etc.

If the data are not rejected in step 66, the process proceeds to step68. In step 68, the color data may be processed in a desired manner toproduce output color/optical measurement data. For example, such datamay be normalized in some manner, or adjusted based on temperaturecompensation or other data detected by the system. The data also may beconverted to different display or other formats, depending on theintended use of the data. In addition, the data indicative of thetranslucence of the object also may be quantified and/or displayed instep 68. After step 68, the process may proceed to starting step 49, orthe process may be terminated, etc.

In accordance with the process illustrated in FIG. 6, three lightintensity values (P1, P2 and IS) are stored per receiver fiber optic tomake color and translucency, etc., measurements. If stored peak valuesP1 and P2 are not equal (for some or all of the receivers), this is anindication that the probe was not held steady over one area, and thedata may be rejected (in other embodiments, the data may not berejected, although the resulting data may be used to produce an averageof the measured data). In addition, peak values P1 and P2 for the threeneutral density perimeter fiber optics should be equal or approximatelyequal; if this is not the case, then this is an indication that theprobe was not held perpendicular or a curved surface is being measured.In other embodiments, the system attempts to compensate for curvedsurfaces and/or non-perpendicular angles. In any event, if the systemcannot make a color/optical measurement, or if the data is rejectedbecause peak values P1 and P2 are unequal to an unacceptable degree,then the operator is notified so that another measurement or otheraction may be taken (such as adjust the sensitivity).

With a system constructed and operating as described above,color/optical measurements may be taken of an object, with accepted datahaving height and angular dependencies removed. Data not taken at thecritical height, or data not taken with the probe perpendicular to thesurface of the object being measured, etc., are rejected in a preferredembodiment of the present invention. In other embodiments, data receivedfrom the perimeter fiber optics may be used to calculate the angle ofthe probe with respect to the surface of the object being measured, andin such embodiments non-perpendicular or curved surface data may becompensated instead of rejected. It also should be noted that peakvalues P1 and P2 for the neutral density perimeter fiber optics providea measure of the luminance (gray value) of the surface of the objectbeing measured, and also may serve to quantify the color value.

The translucency of the object being measured may be quantified as aratio or percentage, such as, for example, (IS/P1)×100%. In otherembodiments, other methods of quantifying translucency data provided inaccordance with the present invention are utilized, such as some otherarithmetic function utilizing IS and P1 or P2, etc.

In another particular aspect of the present invention, data generated inaccordance with the present invention may be used to implement anautomated material mixing/generation machine. Certain objects/materials,such as dental prostheses, are made from porcelain or otherpowders/materials that may be combined in the correct ratios to form thedesired color of the object/prosthesis. Certain powders often containpigments that generally obey Beer's law and/or act in accordance withKubelka-Munk equations and/or Saunderson equations (if needed) whenmixed in a recipe. Color and other data taken from a measurement inaccordance with the present invention may be used to determine orpredict desired quantities of pigment or other materials for the recipe.Porcelain powders and other materials are available in different colors,opacities, etc. Certain objects, such as dental prostheses, may belayered to simulate the degree of translucency of the desired object(such as to simulate a human tooth). Data generated in accordance withthe present invention also may be used to determine the thickness andposition of the porcelain or other material layers to more closelyproduce the desired color, translucency, surface characteristics, etc.In addition, based on fluorescence data for the desired object, thematerial recipe may be adjusted to include a desired quantity offluorescing-type material. In yet other embodiments, surfacecharacteristics (such as texture) information (as more fully describedherein) may be used to add a texturing material to the recipe, all ofwhich may be carried out in accordance with the present invention.

For more information regarding such pigment-material recipe typetechnology, reference may be made to: “The Measurement of Appearance,”Second Edition, edited by Hunter and Harold, copyright 1987; “Principlesof Color Technology,” by Billmeyer and Saltzman, copyright 1981; and“Pigment Handbook,” edited by Lewis, copyright 1988. All of theforegoing are believed to have been published by John Wiley & Sons,Inc., New York, N.Y., and all of which are hereby incorporated byreference.

In certain operative environments, such as dental applications,contamination of the probe is of concern. In certain embodiments of thepresent invention, implements to reduce such contamination are provided.

FIGS. 7A and 7B illustrate a protective cap that may be used to fit overthe end of probe tip 1. Such a protective cap consists of body 80, theend of which is covered by optical window 82, which in a preferredembodiment consists of a structure having a thin sapphire window. In apreferred embodiment, body 80 consists of stainless steel. Body 80 fitsover the end of probe tip 1 and may be held into place by, for example,indentations formed in body 80, which fit with ribs 84 (which may be aspring clip or other retainer) formed on probe tip 1. In otherembodiments, other methods of affixing such a protective cap to probetip 1 are utilized. The protective cap may be removed from probe tip 1and sterilized in a typical autoclave, hot steam, chemiclave or othersterilizing system.

The thickness of the sapphire window should be less than the criticalheight of the probe in order to preserve the ability to detect peakingin accordance with the present invention, and preferably has a thicknessless than the minimal height at which the source/receiver cones overlap(see FIGS. 4B and 4C). It also is believed that sapphire windows may bemanufactured in a reproducible manner, and thus any light attenuationfrom one cap to another may be reproducible. In addition, any distortionof the color/optical measurements produced by the sapphire window may becalibrated out by microprocessor 10.

Similarly, in other embodiments body 80 has a cap with a hole in thecenter (as opposed to a sapphire window), with the hole positioned overthe fiber optic source/receivers. The cap with the hole serves toprevent the probe from coming into contact with the surface, therebyreducing the risk of contamination. It should be noted that, with suchembodiments, the hole is positioned so that the light from/to the lightsource/receiver elements of the probe tip is not adversely affected bythe cap.

FIGS. 8A and 8B illustrate another embodiment of a removable probe tipthat may be used to reduce contamination in accordance with the presentinvention. As illustrated in FIG. 8A, probe tip 88 is removable, andincludes four (or a different number, depending upon the application)fiber optic connectors 90, which are positioned within optical guard 92.Optical guard 92 serves to prevent “cross talk” between adjacent fiberoptics. As illustrated in FIG. 8B, in this embodiment removable tip 88is secured in probe tip housing 92 by way of spring clip 96 (otherremovable retaining implements are utilized in other embodiments). Probetip housing 92 may be secured to base connector 94 by a screw or otherconventional fitting. It should be noted that, with this embodiment,different size tips may be provided for different applications, and thatan initial step of the process may be to install the properly-sized (orfitted tip) for the particular application. Removable tip 88 also may besterilized in a typical autoclave, hot steam, chemiclave or othersterilizing system, or disposed of. In addition, the entire probe tipassembly is constructed so that it may be readily disassembled forcleaning or repair. In certain embodiments the light source/receiverelements of the removable tip are constructed of glass, silica orsimilar materials, thereby making them particularly suitable forautoclave or similar high temperature/pressure cleaning methods, whichin certain other embodiments the light source/receiver elements of theremovable tip are constructed of plastic or other similar materials,which may be of lower cost, thereby making them particularly suitablefor disposable-type removable tips, etc.

In still other embodiments, a plastic, paper or other type shield (whichmay be disposable, cleanable/reusable or the like) may be used in orderto address any contamination concerns that may exist in the particularapplication. In such embodiments, the methodology may includepositioning such a shield over the probe tip prior to takingcolor/optical measurements, and may include removing anddisposing/cleaning the shield after taking color/optical measurements,etc.

With reference to FIG. 9, a tristimulus embodiment of the presentinvention will now be described. In general, the overall system depictedin FIG. 1 and discussed in detail elsewhere herein may be used with thisembodiment. FIG. 9 illustrates a cross section of the probe tip fiberoptics used in this embodiment.

Probe tip 100 includes central source fiber optic 106, surrounded by(and spaced apart from) three perimeter receiver fiber optics 104 andthree color receiver fiber optics 102. Three perimeter receiver fiberoptics 104 are optically coupled to neutral density filters and serve asheight/angle sensors in a manner analogous to the embodiment describeabove. Three color receiver fiber optics are optically coupled tosuitable tristimulus filters, such as red, green and blue filters. Withthis embodiment, a measurement may be made of tristimulus color valuesof the object, and the process described with reference to FIG. 6generally is applicable to this embodiment. In particular, perimeterfiber optics 104 may be used to detect simultaneous peaking or otherwisewhether the probe is perpendicular to the object being measured. Inaddition, taking color measurement data at the critical height also maybe used with this embodiment.

FIG. 10A illustrates an embodiment of the present invention, similar tothe embodiment discussed with reference to FIG. 9. Probe tip 100includes central source fiber optic 106, surrounded by (and spaced apartfrom) three perimeter receiver fiber optics 104 and a plurality of colorreceiver fiber optics 102. The number of color receiver fiber optics102, and the filters associated with such receiver fiber optics 102, maybe chosen based upon the particular application. As with the embodimentof FIG. 9, the process described with reference to FIG. 6 generally isapplicable to this embodiment.

FIG. 10B illustrates an embodiment of the present invention in whichthere are a plurality of receiver fiber optics that surround centralsource fiber optic 240. The receiver fiber optics are arranged in ringssurrounding the central source fiber optic. FIG. 10B illustrates threerings of receiver fiber optics (consisting of fiber optics 242, 244 and246, respectively), in which there are six receiver fiber optics perring. The rings may be arranged in successive larger circles asillustrated to cover the entire area of the end of the probe, with thedistance from each receiver fiber optic within a given ring to thecentral fiber optic being equal (or approximately so). Central fiberoptic 240 is utilized as the light source fiber optic and is connectedto the light source in a manner similar to light source fiber optic 5illustrated in FIG. 1.

The plurality of receiver fiber optics are each coupled to two or morefiber optics in a manner similar to the arrangement illustrated in FIG.1 for splicing connector 4. One fiber optic from such a splicingconnector for each receiver fiber optic passes through a neutral densityfilter and then to light sensor circuitry similar to the light sensorcircuitry illustrated in FIG. 3. A second fiber optic from the splicingconnector per receiver fiber optic passes through a Sharp CuttingWrattan Gelatin Filter and then to light sensor circuitry as discussedelsewhere herein. Thus, each of the receiver fiber optics in the probetip includes both color measuring elements and neutral light measuringor “perimeter” elements.

FIG. 10D illustrates the geometry of probe 260 (such as described above)illuminating an area on flat diffuse surface 272. Probe 260 createslight pattern 262 that is reflected diffusely from surface 272 inuniform hemispherical pattern 270. With such a reflection pattern, thereflected light that is incident upon the receiving elements in theprobe will be equal (or nearly equal) for all elements if the probe isperpendicular to the surface as described above herein.

FIG. 10C illustrates a probe illuminating rough surface 268 or a surfacethat reflects light spectrally. Spectral reflected light will exhibithot spots or regions where the reflected light intensity is considerablygreater than it is on other areas. The reflected light pattern will beuneven when compared to a smooth surface as illustrate in FIG. 10D.

Since a probe as illustrated in FIG. 10B has a plurality of receiverfiber optics arranged over a large surface area, the probe may beutilized to determine the surface texture of the surface as well asbeing able to measure the color and translucency, etc., of the surfaceas described earlier herein. If the light intensity received by thereceiver fiber optics is equal for all fiber optics within a given ringof receiver fiber optics, then generally the surface is diffuse andsmooth. If, however, the light intensity of receiver fibers in a ringvaries with respect to each other, then generally the surface is roughor spectral. By comparing the light intensities measured within receiverfiber optics in a given ring and from ring to ring, the texture andother characteristics of the surface may be quantified.

FIG. 11 illustrates an embodiment of the present invention in whichlinear optical sensors and a color gradient filter are utilized insteadof light sensors 8 (and filters 22, etc.). Receiver fiber optics 7,which may be optically coupled to probe tip 1 as with the embodiment ofFIG. 1, are optically coupled to linear optical sensor 112 through colorgradient filter 110. In this embodiment, color gradient filter 110 mayconsist of series of narrow strips of cut-off type filters on atransparent or open substrate, which are constructed so as topositionally correspond to the sensor areas of linear optical sensor112. An example of a commercially available linear optical sensor 112 isTexas Instruments part number TSL213, which has 61 photo diodes in alinear array. Light receiver fiber optics 7 are arranged correspondinglyin a line over linear optical sensor 112. The number of receiver fiberoptics may be chosen for the particular application, so long as enoughare included to more or less evenly cover the full length of colorgradient filter 110. With this embodiment, the light is received andoutput from receiver fiber optics 7, and the light received by linearoptical sensor 112 is integrated for a short period of time (determinedby the light intensity, filter characteristics and desired accuracy).The output of linear array sensor 112 is digitized by ADC 114 and outputto microprocessor 116 (which may the same processor as microprocessor 10or another processor).

In general, with the embodiment of FIG. 1, perimeter receiver fiberoptics may be used as with the embodiment of FIG. 1, and in general theprocess described with reference to FIG. 6 is applicable to thisembodiment.

FIG. 12 illustrates an embodiment of the present invention in which amatrix optical sensor and a color filter grid are utilized instead oflight sensors 8 (and filters 22, etc.). Receiver fiber optics 7, whichmay be optically coupled to probe tip 1 as with the embodiment of FIG.1, are optically coupled to matrix optical sensor 122 through filtergrid 120. Filter grid 120 is a filter array consisting of a number ofsmall colored spot filters that pass narrow bands of visible light.Light from receiver fiber optics 7 pass through corresponding filterspots to corresponding points on matrix optical sensor 122. In thisembodiment, matrix optical sensor 122 may be a monochrome optical sensorarray, such as CCD-type or other type of light sensor element such asmay be used in a video camera. The output of matrix optical sensor 122is digitized by ADC 124 and output to microprocessor 126 (which may thesame processor as microprocessor 10 or another processor). Under controlof microprocessor 126, matrix optical sensor 126 collects data fromreceiver fiber optics 7 through color filter grid 120.

In general, with the embodiment of FIG. 12, perimeter receiver fiberoptics may be used as with the embodiment of FIG. 1, and in general theprocess described with reference to FIG. 6 also is applicable to thisembodiment.

As will be clear from the foregoing description, with the presentinvention a variety of types of spectral color/optical photometers (ortristimulus-type calorimeters) may be constructed, with perimeterreceiver fiber optics used to collect color/optical data essentiallyfree from height and angular deviations. In addition, in certainembodiments, the present invention enables color/optical measurements tobe taken at a critical height from the surface of the object beingmeasured, and thus color/optical data may be taken without physicalcontact with the object being measured (in such embodiments, thecolor/optical data is taken only by passing the probe through region 1and into region 2, but without necessarily going into region 3 of FIGS.5A and 5B). Such embodiments may be utilized if contact with the surfaceis undesirable in a particular application. In the embodiments describedearlier, however, physical contact (or near physical contact) of theprobe with the object may allow all five regions of FIGS. 5A and 5B tobe utilized, thereby enabling measurements to be taken such thattranslucency information also may be obtained. Both types of embodimentsgenerally are within the scope of the invention described herein.

Additional description will now be provided with respect to cut-offfilters of the type described in connection with the preferredembodiment(s) of FIGS. 1 and 3 (such as filters 22 of FIG. 3). FIG. 13Aillustrates the properties of a single Kodak Sharp Cutting WrattenGelatin Filter discussed in connection with FIG. 3. Such a cut-offfilter passes light below a cut-off frequency (i.e., above a cut-offwavelength). Such filters may be manufactured to have a wide range ofcut-off frequencies/wavelengths. FIG. 13B illustrates a number of suchfilters, twelve in a preferred embodiment, with cut-offfrequencies/wavelengths chosen so that essentially the entire visibleband is covered by the collection of cut-off filters.

FIGS. 14A and 14B illustrate exemplary intensity measurements using acut-off filter arrangement such as illustrated in FIG. 13B, first in thecase of a white surface being measured (FIG. 14A), and also in the caseof a blue surface being measured (FIG. 14B). As illustrated in FIG. 14A,in the case of a white surface, the neutrally filtered perimeter fiberoptics, which are used to detect height and angle, etc., generally willproduce the highest intensity (although this depends at least in partupon the characteristics of the neutral density filters). As a result ofthe stepped cut-off filtering provided by filters having thecharacteristics illustrated in FIG. 13B, the remaining intensities willgradually decrease in value as illustrated in FIG. 14A. In the case of ablue surface, the intensities will decrease in value generally asillustrated in FIG. 14B. Regardless of the surface, however, theintensities out of the filters will always decrease in value asillustrated, with the greatest intensity value being the output of thefilter having the lowest wavelength cut-off value (i.e., passes allvisible light up to blue), and the lowest intensity value being theoutput of the filter having the highest wavelength cut-off (i.e., passesonly red visible light). As will be understood from the foregoingdescription, any color data detected that does not fit the decreasingintensity profiles of FIGS. 14A and 14B may be detected as anabnormality, and in certain embodiments detection of such a conditionresults in data rejection, generation of an error message or initiationof a diagnostic routine, etc.

Reference should be made to the FIGS. 1 and 3 and the relateddescription for a detailed discussion of how such a cut-off filterarrangement may be utilized in accordance with the present invention.

FIG. 15 is a flow chart illustrating audio tones that may be used incertain preferred embodiments of the present invention. It has beendiscovered that audio tones (such as tones, beeps, voice or the likesuch as will be described) present a particularly useful and instructivemeans to guide an operator in the proper use of a color measuring systemof the type described herein.

The operator may initiate a color/optical measurement by activation of aswitch (such as switch 17 of FIG. 1) at step 150. Thereafter, if thesystem is ready (set-up, initialized., calibrated, etc.), alower-the-probe tone is emitted (such as through speaker 16 of FIG. 1)at step 152. The system attempts to detect peak intensity P1 at step154. If a peak is detected, at step 156 a determination is made whetherthe measured peak P1 meets the applicable criteria (such as discussedabove in connection with FIGS. 5A, 5B and 6). If the measured peak P1 isaccepted, a first peak acceptance tone is generated at step 160. If themeasured peak P1 is not accepted, an unsuccessful tone is generated atstep 158, and the system may await the operator to initiate a furthercolor/optical measurement. Assuming that the first peak was accepted,the system attempts to detect peak intensity P2 at step 162. If a secondpeak is detected, at step 164 a determination is made whether themeasured peak P2 meets the applicable criteria. If the measured peak P2is accepted the process proceeds to color calculation step 166 (in otherembodiments, a second peak acceptance tone also is generated at step166). If the measured peak P2 is not accepted, an unsuccessful tone isgenerated at step 158, and the system may await the operator to initiatea further color/optical measurement. Assuming that the second peak wasaccepted, a color/optical calculation is made at step 166 (such as, forexample, microprocessor 10 of FIG. 1 processing the data output fromlight sensors 8, etc.). At step 168, a determination is made whether thecolor calculation meets the applicable criteria. If the colorcalculation is accepted, a successful tone is generated at step 170. Ifthe color calculation is not accepted, an unsuccessful tone is generatedat step 158, and the system may await the operator to initiate a furthercolor/optical measurement.

With unique audio tones presented to an operator in accordance with theparticular operating state of the system, the operator's use of thesystem may be greatly facilitated. Such audio information also tends toincrease operator satisfaction and skill level, as, for example,acceptance tones provide positive and encouraging feedback when thesystem is operated in a desired manner.

The color/optical measuring systems and methods in accordance with thepresent invention may be applied to particular advantage in the field ofdentistry, as will be more fully explained hereinafter. In particularthe present invention includes the use of such systems and methods tomeasure the color and other attributes of a tooth in order to prepare adental prosthesis or intraoral tooth-colored fillings, or to selectdenture teeth or to determine a suitable cement color forporcelain/resin prostheses. The present invention also provides methodsfor storing and organizing measured data such as in the form of apatient database.

FIG. 16 is a flow chart illustrating a general dental applicationprocess flow for use of the color/optical measuring systems and methodsin accordance with the present invention. At step 200, the color/opticalmeasuring system may be powered-up and stabilized, with any requiredinitialization or other setup routines performed. At step 200, anindication of the system status may be provided to the operator, such asthrough LCD 14 or speaker 16 of FIG. 1. Also at step 200, the probe tipmay be shielded or a clean probe tip may be inserted in order to reducethe likelihood of contamination (see, e.g., FIGS. 7A to 8B and relateddescription). In other embodiments, a plastic or other shield may alsobe used (which may be disposable, cleanable/reusable, etc., aspreviously described), so long as it is constructed and/or positioned soas to not adversely affect the measurement process.

At step 202, the patient and the tooth to be measured are prepared. Anyrequired cleaning or other tooth preparation would be performed at step202. Any required patient consultation about the type of prosthesis orarea of a tooth to be matched would be performed at (or before) step202. In certain embodiments, a positioning device is prepared at step202, such as is illustrated in FIGS. 17A and 17B. In such embodiments,for example, a black or other suitably-colored material 282, which mayadhere to tooth 280 (such as with a suitable adhesive), is formed tohave opening 281 larger than the diameter of the measuring probe, withopening 281 centered on the area of tooth 280 to be measured. Thematerial of positioning device 282 is formed in a manner to fit on/overtooth 280 (such as over the incisal edge of tooth 280 and/or over one ormore adjacent teeth) so that it may be placed on/over tooth 280 in arepeatable manner. Such a positioning device may serve to ensure thatthe desired area of tooth 280 is measured, and also allows for repeatmeasurements of the same area for purposes of confirmation or the like.Any other pre-measurement activities may be performed at (or before)step 202.

At step 204, the operator (typically a dentist or other dentalprofessional) moves the probe towards the area of the tooth to bemeasured. This process preferably is conducted in accordance with themethodology described with reference to FIGS. 5A, 5B and 6, andpreferably is accompanied by audio tones such as described withreference to FIG. 15. With the present invention, the operator mayobtain color and translucency data, etc., for example, from a desiredarea of the tooth to be measured. During step 204, an acceptedcolor/optical measurement is made, or some indication is given to theoperator that the measurement step needs to be repeated or some otheraction taken. After an accepted color/optical measurement is made atstep 204, for example, the dentist may operate on the desired tooth orteeth or take other action. Before or after such action, additionalmeasurements may be taken as needed (see, e.g., FIG. 18 and relateddescription).

Upon successful completion of one or more measurements taken at step204, the process proceeds to step 206. At step 206, any data conversionor processing of data collected at step 204 may be performed. Forexample, in the embodiment of FIG. 1, detailed color spectrum andtranslucency information may be generated. In a particular dentalapplication, however, it may be that a dental lab, for example, requiresthat the color be presented in Munsell format (i.e., chroma, hue andvalue), RGB values, XYZ coordinates, CIELAB values, Hunter values, orsome other color data format. With the spectral/color informationproduced by the present invention, data may be converted to such formatsthrough conventional matrix math, for example. Such math may beperformed by microprocessor 10 or computer 13A of FIG. 1, or in someother manner. It also should be noted that, in certain embodiments, thedata produced at step 204 in accordance with the present invention maybe used directly without data conversion. In such embodiments, step 206may be omitted. In other embodiments, step 206 consists of dataformatting, such as preparing the data for reproduction in hard copy,pictorial or other form, or for transmission as facsimile or modem data.Finally, in certain embodiments a translucency factor is computed in aformat suitable for the particular application. In yet otherembodiments, a surface texture or detail factor is computed in a formatsuitable for the particular application.

At step 208, a matching is optionally attempted between the dataproduced at steps 204 and 206 (if performed) and a desired color (inother embodiments, the process may proceed from 204 directly to 210, oralternatively steps 206 and 208 may be combined). For example, a numberof “shade guides” are available in the market, some of which are knownin the industry as Vita shade guides, Bioform shade guides or othercolor matching standards, guides or references or custom shade guides.In certain preferred embodiments, a lookup table is prepared and loadedinto memory (such as memory associated with microprocessor 10 orcomputer 13A of FIG. 1), and an attempt is made to the closest match ormatches of the collected data with the known shade guides, custom shadeguides or reference values. In certain embodiments, a translucencyfactor and/or a surface texture or detail factor also is used in aneffort to select the best possible match.

In a particular aspect of certain embodiments of the present invention,at step 208 a material correlation lookup table is accessed. Based onthe color and translucency data obtained at step 204, a proposed recipeof materials, pigments or other instruction information is prepared fora prosthesis or filling, etc., of the desired color and translucency,etc. With the detailed color and other information made available inaccordance with the present invention, a direct correlation with therelevant constituent materials may be made. In still other embodiments,such information is made available to an automated mixing ormanufacturing machine for preparation of prosthesis or material of thedesired color and translucency, etc., as more fully described elsewhereherein.

At step 210, based on the results of the preceding steps, theprosthesis, denture, intraoral tooth-colored filling material or otheritems are prepared. This step may be performed at a dental lab, or, incertain embodiments, at or near the dental operatory. For remotepreparation, relevant data produced at steps 204, 206 and/or 208 may besent to the remote lab or facility by hardcopy, facsimile or modem orother transmission. What should be understood from the foregoing isthat, based on data collected at step 204, a prosthesis may be preparedof a desirable color and/or other optical characteristic at step 210.

At step 212, the prosthesis or other material prepared at step 210 maybe measured for confirmation purposes, again preferably conducted inaccordance with the methodology described with reference to FIGS. 5A, 5Band 6, and preferably accompanied by audio tones such as described withreference to FIG. 15. A re-measure of the tooth in the patient's mouth,etc. also may be made at this step for confirmation purposes. If theconfirmation process gives satisfactory results, the prosthesis,denture, composite filling or other material may be preliminarilyinstalled or applied in the patient at step 214. At step 216, are-measure of the prosthesis, denture, composite filling or othermaterials optionally may be made. If the results of step 216 areacceptable, then the prosthesis may be more permanently installed orapplied in the patient at step 218. If the results of step 216 are notacceptable, the prosthesis may be modified and/or other of the stepsrepeated as necessary in the particular situation.

In another particular aspect of the present invention, for example, dataprocessing such as illustrated in FIG. 18 may be taken in conjunctionwith the process of FIG. 16. At step 286, client database software isrun on a computing device, such as computer 13A of FIG. 1. Such softwaremay include data records for each patient, including fields storing thehistory of dental services performed on the patient, informationregarding the status or condition of the patient's teeth, billing,address and other information. Such software may enter a mode by whichit is in condition to accept color or other data taken in accordancewith the present invention.

At step 288, for example, the dentist or other dental professional mayselect parameters for a particular tooth of the patient to be measured.Depending on the size and condition of the tooth (such as color gradientor the like), the dentist may sector the tooth into one or more regions,such as a grid. Thus, for example, in the case of tooth for which it isdecided to take four measurements, the tooth may be sectored into fourregions. Such parameters, which may include a pictorial representationon the computer of the tooth sectored into four regions (such as by gridlines), along with tooth identification and patient information may beentered into the computer at this time.

At step 290, one or more measurements of the tooth may be taken, such aswith a system and method as described in connection with FIGS. 1, 5A, 5Band/or 6. The number of such measurements preferably is associated withthe parameters entered at step 288. Thereafter, at step 292, the datacollected from the measurement(s) may be sent to the computer forsubsequent processing. As an illustrative example, four color/opticalmeasurements may be taken (for the four regions of the tooth in theabove example) and sent to the computer, with the data for the fourcolor/optical measurements (such as RGB or other values) associated withthe four regions in accordance with the entered parameters. Also as anexample, the displayed pictorial representation of the tooth may haveoverlaid thereof data indicative of the color/optical measurement(s). Atstep 294, such as after completion of color/optical measurements on theparticular patient, the data collected during the process may beassociatively stored as a part of the patient's dental records in thedata base. In embodiments accompanied by use of an intraoral camera, forexample (see, e.g., FIG. 19 and related description), captured images ofone or more of the patient's teeth also may be associatively stored aspart of the patient's dental records. In certain embodiments, a picturecaptured by the intraoral camera is overlaid with grid or sector lines(such as may be defined in step 288), with color or other data measuredas described herein also overlaid over the captured image. In such amanner, the color or other data may be electronically and visuallyassociated with a picture of the particular measured tooth, therebyfacilitating the use of the system and the understanding of thecollected data. In still other embodiments, all such captured image andcolor measurement records include a time and/or date, so that a recordof the particular history of a particular tooth of a particular patientmay be maintained. See FIGS. 24 to 26 and related description foradditional embodiments utilizing an intraoral camera, etc., inaccordance with the present invention.

In yet another particular aspect of the present invention, a measuringdevice and method (such as described elsewhere herein) may be combinedwith an intraoral camera and other implements. As illustrated in FIG.19, control unit 300 contains conventional electronics and circuitry,such as power supplies, control electronics, light sources and the like.Coupled to control unit 300 is intraoral camera 301 (for viewing, andcapturing images of, a patient's tooth or mouth, etc.), curing light 302(such as for curing light-cured intraoral filling material), measuringdevice 304 (such as described elsewhere herein), and visible light 306(which may be an auxiliary light for intraoral examinations and thelike). With such embodiments, color, translucency, fluorescence, surfacetexture and/or other data collected for a particular tooth frommeasuring device 304 may be combined with images captured by intraoralcamera 301, with the overall examination and processing of the patientfacilitated by having measuring device 304, intraoral camera 301, curinglight 302 and visible light 306 integrated into a single unit. Suchintegration serves to provide synergistic benefits in the use of theinstruments, while also reducing costs and saving physical space. Inanother particular aspect of such embodiments, the light source formeasuring device 304 and intraoral camera 301 are shared, therebyresulting in additional benefits.

Further embodiments of the present invention will now be described withreference to FIGS. 20 to 23. The previously described embodimentsgenerally rely on movement of the probe with respect to the object/toothbeing measured. While such embodiments provide great utility in manyapplications, in certain applications, such as robotics, industrialcontrol, automated manufacturing, etc. (such as positioning the objectand/or the probe to be in proximity to each other, detectingcolor/optical properties of the object, and then directing the object,e.g., sorting, based on the detected color/optical properties, forfurther industrial processing, packaging, etc.) it may be desired tohave the measurement made with the probe held or positionedsubstantially stationary above the surface of the object to be measured(in such embodiments, the positioned probe may not be handheld as withcertain other embodiments). Such embodiments also may have applicabilityin the field of dentistry (in such applications, “object” generallyrefers to a tooth, etc.).

FIG. 20 illustrates such a further embodiment. The probe of thisembodiment includes a plurality of perimeter sensors and a plurality ofcolor sensors coupled to receivers 312-320. The color sensors andrelated components, etc., may be constructed to operate in a manneranalogous to previously described embodiments. For example, fiber opticcables or the like may couple light from source 310 that is received byreceivers 312-320 to sharp cutoff filters, with the received lightmeasured over precisely defined wavelengths (see, e.g., FIGS. 1, 3 and11-14 and related description). Color/optical characteristics of theobject may be determined from the plurality of color sensormeasurements, which may include three such sensors in the case of atristimulus instrument, or 8, 12, 15 or more color sensors for a morefull bandwidth system (the precise number may be determined by thedesired color resolution, etc.).

With this embodiment, a relatively greater number of perimeter sensorsare utilized (as opposed, for example, to the three perimeter sensorsused in certain preferred embodiments of the present invention). Asillustrated in FIG. 20, a plurality of triads of receivers 312-320coupled to perimeter sensors are utilized, where each triad in thepreferred implementation consists of three fiber optics positioned equaldistance from light source 310, which in the preferred embodiment is acentral light source fiber optic. The triads of perimeterreceivers/sensors may be configured as concentric rings of sensorsaround the central light source fiber optic. In FIG. 20, ten such triadrings are illustrated, although in other embodiments a lesser or greaternumber of triad rings may be utilized, depending upon the desiredaccuracy and range of operation, as well as cost considerations and thelike.

The probe illustrated in FIG. 20 may operate within a range of heights(i.e., distances from the object being measured). As with earlierembodiments, such height characteristics are determined primarily by thegeometry and constituent materials of the probe, with the spacing of theminimal ring of perimeter sensors determining the minimal height, andthe spacing of the maximal ring of perimeter sensors determining themaximum height, etc. It therefore is possible to construct probes ofvarious height ranges and accuracy, etc., by varying the number ofperimeter sensor rings and the range of ring distances from the centralsource fiber optic. It should be noted that such embodiments may beparticularly suitable when measuring similar types of materials, etc.

As described earlier, the light receiver elements for the plurality ofreceivers/perimeter sensors may be individual elements such as TexasInstruments TSL230 light-to-frequency 1.5 converters, or may beconstructed with rectangular array elements or the like such as may befound in a CCD camera. Other broadband-type of light measuring elementsare utilized in other embodiments. Given the large number of perimetersensors used in such embodiments (such as 30 for the embodiment of FIG.16), an array such as CCD camera-type sensing elements may be desirable.It should be noted that the absolute intensity levels of light measuredby the perimeter sensors is not as critical to such embodiments of thepresent invention; in such embodiments differences between the triads ofperimeter light sensors are advantageously utilized in order to obtainoptical measurements.

Optical measurements may be made with such a probe byholding/positioning the probe near the surface of the object beingmeasured (i.e., within the range of acceptable heights of the particularprobe). The light source providing light to light source 310 is turnedon and the reflected light received by receivers 312-320 (coupled to theperimeter sensors) is measured. The light intensity of the rings oftriad sensors is compared. Generally, if the probe is perpendicular tothe surface and if the surface is flat, the light intensity of the threesensors of each triad should be approximately will be equal. If theprobe is not perpendicular to the surface or if the surface is not flat,the light intensity of the three sensors within a triad will not beequal. It is thus possible to determine if the probe is perpendicular tothe surface being measured, etc. It also is possible to compensate fornon-perpendicular surfaces by mathematically adjusting the lightintensity measurements of the color sensors with the variance inmeasurements of the triads of perimeters sensors.

Since the three sensors forming triads of sensors are at differentdistances (radii) from central light source 310, it is expected that thelight intensities measured by light receivers 312-320 and the perimetersensors will vary. For any given triad of sensors, as the probe is movedcloser to the surface, the received light intensity will increase to amaximum and then sharply decrease as the probe is moved closer to thesurface. As with previously-described embodiments, the intensitydecreases rapidly as the probe is moved less than the critical heightand decreases rapidly to zero or almost zero for opaque objects. Thevalue of the critical height depends principally upon the distance ofthe particular receiver from light source 310. Thus, the triads ofsensors will peak at different critical heights. By analyzing thevariation in light values received by the triads of sensors, the heightof the probe can be determined. Again, this is particularly true whenmeasuring similar types of materials.

The system initially is calibrated against a neutral background (e.g., agray background), and the calibration values are stored in non-volatilememory (see, e.g., processor 10 of FIG. 1). For any given color orintensity, the intensity for the receivers/perimeter sensors(independent of distance from the central source fiber optic) in generalshould vary equally. Hence, a white surface should produce the highestintensities for the perimeter sensors, and a black surface will producethe lowest intensities. Although the color of the surface will affectthe measured light intensities of the perimeter sensors, it shouldaffect them substantially equally. The height of the probe from thesurface of the object, however, will affect the triads of sensorsdifferently. At the minimal height range of the probe, the triad ofsensors in the smallest ring (those closest to the source fiber optic)will be at or about their maximal value. The rest of the rings of triadswill be measuring light at intensities lower than their maximal values.As the probe is raised/positioned from the minimal height, the intensityof the smallest ring of sensors will decrease and the intensity of thenext ring of sensors will increase to a maximal value and will thendecrease in intensity as the probe is raised/positioned still further.Similarly for the third ring, fourth ring and so on. Thus, the patternof intensities measured by the rings of triads will be height dependent.In such embodiments, characteristics of this pattern may be measured andstored in non-volatile RAM look-up tables (or the like) for the probe bycalibrating it in a fixture using a neutral color surface. Again, theactual intensity of light is not as important in such embodiments, butthe degree of variance from one ring of perimeter sensors to another is.

To determine a measure of the height of the probe from the surface beingmeasured, the intensities of the perimeter sensors (coupled to receivers312-320) is measured. The variance in light intensity from the innerring of perimeter sensors to the next ring and so on is analyzed andcompared to the values in the look-up table to determine the height ofthe probe. The determined height of the probe with respect to thesurface thus may be utilized by the system processor to compensate forthe light intensities measured by the color sensors in order to obtainreflectivity readings that are in general independent of height. As withpreviously described embodiments, the reflectivity measurements may thenbe used to determine optical characteristics of the object beingmeasured, etc.

It should be noted that audio tones, such as previously described, maybe advantageously employed when such an embodiment is used in a handheldconfiguration. For example, audio tones of varying pulses, frequenciesand/or intensities may be employed to indicate the operational status ofthe instrument, when the instrument is positioned within an acceptablerange for color measurements, when valid or invalid color measurementshave been taken, etc. In general, audio tones as previously describedmay be adapted for advantageous use with such further embodiments.

FIG. 21 illustrates a further such embodiment of the present invention.The preferred implementation of this embodiment consists of a centrallight source 310 (which in the preferred implementation is a centrallight source fiber optic), surrounded by a plurality of light receivers322 (which in the preferred implementation consists of three perimeterlight receiver fiber optics). The three perimeter light receiver fiberoptics, as with earlier described embodiments, may be each spliced intoadditional fiber optics that pass to light intensity receivers/sensors,which may be implemented with Texas Instruments TSL230 light tofrequency converters as described previously. One fiber of eachperimeter receiver is coupled to a sensor and measured full band width(or over substantially the same bandwidth) such as via a neutral densityfilter, and other of the fibers of the perimeter receivers are coupledto sensors so that the light passes through sharp cut off or notchfilters to measure the light intensity over distinct frequency ranges oflight (again, as with earlier described embodiments). Thus there arecolor light sensors and neutral “perimeter” sensors as with previouslydescribed embodiments. The color sensors are utilized to determine thecolor or other optical characteristics of the object, and the perimetersensors are utilized to determine if the probe is perpendicular to thesurface and/or are utilized to compensate for nonperpendicular angleswithin certain angular ranges.

In the embodiment of FIG. 21, the angle of the perimeter sensor fiberoptics is mechanically varied with respect to the central source fiberoptic. The angle of the perimeter receivers/sensors with respect to thecentral source fiber optic is measured and utilized as describedhereinafter. An exemplary mechanical mechanism, the details of which arenot critical so long as desired, control movement of the perimeterreceivers with respect to the light source is obtained, is describedwith reference to FIG. 22.

The probe is held within the useful range of the instrument (determinedby the particular configuration and construction, etc.), and a colormeasurement is initiated. The angle of the perimeter receivers/sensorswith respect to the central light source is varied from parallel topointing towards the central source fiber optic. While the angle isbeing varied, the intensities of the light sensors for the perimetersensors (e.g., neutral sensors) and the color sensors is measured andsaved along with the angle of the sensors at the time of the lightmeasurement. The light intensities are measured over a range of angles.As the angle is increased the light intensity will increase to a maximumvalue and will then decrease as the angle is further increased. Theangle where the light values is a maximum is utilized to determine theheight of the probe from the surface. As will be apparent to thoseskilled in the art based on the teachings provided herein, with suitablecalibration data, simple geometry may be utilized to calculate theheight based on the data measured during variation of the angle. Theheight measurement may then be utilized to compensate for the intensityof the color/optical measurements and/or utilized to normalize colorvalues, etc.

FIG. 22 illustrates an exemplary embodiment of a mechanical arrangementto adjust and measure the angle of the perimeter sensors. Each perimeterreceiver/sensor 322 is mounted with pivot arm 326 on probe frame 328.Pivot arm 326 engages central ring 332 in a manner to form a cammechanism. Central ring 332 includes a groove that holds a portion ofpivot arm 326 to form the cam mechanism. Central ring 332 may be movedperpendicular with respect to probe frame 328 via linear actuator 324and threaded spindle 330. The position of central ring 332 with respectto linear actuator 324 determines the angle of perimeterreceivers/sensors 322 with respect to light source 310. Such angularposition data vis-a-vis the position of linear actuator 324 may becalibrated in advance and stored in non-volatile memory, and later usedto produce color/optical characteristic measurement data as previouslydescribed.

A further embodiment of the present invention utilizing an alternateremovable probe tip will now be described with reference to FIGS.23A-23C. As illustrated in FIG. 23A, this embodiment utilizes removable,coherent light conduit 340 as a removable tip. Light conduit 340 is ashort segment of a light conduit that preferably may be a fused bundleof small fiber optics, in which the fibers are held essentially parallelto each other, and the ends of which are highly polished. Cross-section350 of light conduit 340 is illustrated in FIG. 23B. Light conduitssimilar to light conduit 340 have been utilized in what are known asborescopes, and also have been utilized in medical applications such asendoscopes.

Light conduit 340 in this embodiment serves to conduct light from thelight source to the surface of the object being measured, and also toreceive reflected light from the surface and conduct it to lightreceiver fiber optics 346 in probe handle 344. Light conduit 340 is heldin position with respect to fiber optics 346 by way or compression jaws342 or other suitable fitting or coupled that reliably positions lightconduit 340 so as to couple light effectively to/from fiber optics 346.Fiber optics 346 may be separated into separate fibers/light conduits348, which may be coupled to appropriate light sensors, etc., as withpreviously described embodiments.

In general, the aperture of the fiber optics used in light conduit 340may be chosen to match the aperture of the fiber optics for the lightsource and the light receivers. Thus, the central part of the lightconduit may conduct light from the light source and illuminate thesurface as if it constituted a single fiber within a bundle of fibers.Similarly, the outer portion of the light conduit may receive reflectedlight and conduct it to light receiver fiber optics as if it constitutedsingle fibers. Light conduit 340 has ends that preferably are highlypolished and cut perpendicular, particularly the end coupling light tofiber optics 346. Similarly, the end of fiber optics 346 abutting lightconduit 340 also is highly polished and cut perpendicular to a highdegree of accuracy in order to minimize light reflection and cross talkbetween the light source fiber optic and the light receiver fiber opticsand between adjacent receiver fiber optics. Light conduit 340 offerssignificant advantages including in the manufacture and installation ofsuch a removable tip. For example, the probe tip need not beparticularly aligned with the probe tip holder; rather, it only needs tobe held against the probe tip holder such as with a compressionmechanism (such as with compression jaws 342) so as to couple lighteffectively to/from fiber optics 346. Thus, such a removable tipmechanism may be implemented without alignment tabs or the like, therebyfacilitating easy installation of the removable probe tip. Such an easyinstallable probe tip may thus be removed and cleaned prior toinstallation, thereby facilitating use of the color/optical measuringapparatus by dentists, medical professions or others working in anenvironment in which contamination may be a concern. Light conduit 340also may be implemented, for example, as a small section of lightconduit, which may facilitate easy and low cost mass production and thelike.

A further embodiment of such a light conduit probe tip is illustrated aslight conduit 352 in FIG. 23C. Light conduit 352 is a light conduit thatis narrower on one end (end 354) than the other end (end 356).Contoured/tapered light conduits such as light conduit 352 may befabricated by heating and stretching a bundle of small fiber optics aspart of the fusing process. Such light conduits have an additionalinteresting property of magnification or reduction. Such phenomenaresult because there are the same number of fibers in both ends. Thus,light entering narrow end 354 is conducted to wider end 356, and sincewider end 356 covers a larger area, it has a magnifying affect.

Light conduit 352 of FIG. 23C may be utilized in a manner similar tolight conduit 340 (which in general may be cylindrical) of FIG. 23A.Light conduit 352, however, measures smaller areas because of itsreduced size at end 354. Thus, a relatively larger probe body may bemanufactured where the source fiber optic is spaced widely from thereceiver fiber optics, which may provide an advantage in reduced lightreflection and cross talk at the junction, while still maintaining asmall probe measuring area. Additionally, the relative sizes of narrowend 354 of light conduit 352 may be varied. This enables the operator toselect the size/characteristic of the removable probe tip according tothe conditions in the particular application. Such ability to selectsizes of probe tips provides a further advantage in making opticalcharacteristics measurements in a variety of applications and operativeenvironments.

As should be apparent to those skilled in the art in view of thedisclosures herein, light conduits 340 and 356 of FIGS. 23A and 23C neednot necessarily be cylindrical/tapered as illustrated, but may be curvedsuch as for specialty applications, in which a curved probe tip may beadvantageously employed (such as in a confined or hard-to-reach place).It also should be apparent that light conduit 352 of FIG. 23C may bereversed (with narrow end 354 coupling light into fiber optics 346,etc., and wide end 356 positioned in order to take measurements) inorder to cover larger areas.

Referring now to FIG. 24, a further embodiment of the present inventionwill be explained.

Intraoral reflectometer 380, which may be constructed as describedabove, includes probe 381. Data output from reflectometer 380 is coupledto computer 384 over bus 390 (which may be a standard serial or parallelbus, etc.). Computer 384 includes a video freeze frame capability andpreferably a modem. Intraoral camera 382 includes handpiece 383 andcouples video data to computer 384 over bus 392. Computer 384 is coupledto remote computer 386 over telecommunication channel 388, which may bea standard telephone line, ISDN line, a LAN or WAN connection, etc. Withsuch an embodiment, video measurements may be taken of one or more teethby intraoral camera 382, along with optical measurements taken byintraoral reflectometer 380. Computer 384 may store still picture imagestaken from the output of intraoral camera 382.

Teeth are known to have variations in color from tooth to tooth, andteeth are known to have variations in color over the area of one tooth.Intraoral cameras are known to be useful for showing the details ofteeth. Intraoral cameras, however, in general have poor colorreproducability. This is due to variations in the camera sensingelements (from camera to camera and over time etc.), in computermonitors, printers, etc. As a result of such variations, it presently isnot possible to accurately quantify the color of a tooth with anintraoral camera. With the present embodiment, measuring and quantifyingthe color or other optical properties of teeth may be simplified throughthe use of an intraoral reflectometer in accordance with the presentinvention, along with an intraoral camera.

In accordance with this embodiment, the dentist may capture a stillpicture of a tooth and its adjacent teeth using the freeze frame featureof computer 384. Computer 384, under appropriate software and operatorcontrol, may then “postureize” the image of the tooth and its adjacentteeth, such as by limiting the number of gray levels of the luminancesignal, which can result in a color image that shows contours ofadjacent color boundaries. As illustrated in FIG. 25, such apostureization process may result in teeth 396 being divided intoregions 398, which follow color contours of teeth 396. As illustrated,in general the boundaries will be irregular in shape and follow thevarious color variations found on particular teeth.

With teeth postureized as illustrated in FIG. 25, computer 384 may thenhighlight (such as with a colored border, shading, highlight or thelike) a particular color region on a tooth to be measured, and then thedentist may then measure the highlighted region with intraoralreflectometer 380. The output of intraoral reflectometer 380 is input tocomputer 384 over bus 390, and computer 384 may store in memory or on ahard disk or other storage medium the color/optical data associated withthe highlighted region. Computer 384 may then highlight another regionand continue the process until color/optical data associated with alldesired highlighted regions have been stored in computer 384. Suchcolor/optical data may then be stored in a suitable data base, alongwith the video image and postureized video image of the particularteeth, etc.

Computer 384 may then assess if the measured value of a particular colorregion is consistent with color measurements for adjacent color regions.If, for example, a color/optical measurement for one region indicates adarker region as compared to an adjacent region, but the postureizedimage indicates that the reverse should be true, then computer 384 maynotify the dentist (such as with an audio tone) that one or more regionsshould be re-measured with intraoral reflectometer 380. Computer 384 maymake such relative color determinations (even though the color valuesstored in computer 384 from the freeze frame process are not true colorvalues) because the variations from region to region should follow thesame pattern as the color/optical measurements taken by intraoralreflectometer 380. Thus, if one region is darker than its neighbors,then computer 384 will expect that the color measurement data fromintraoral reflectometer 380 for the one region also will be darkerrelative to color measurement data for the neighboring regions, etc.

As with the color measurement data and captured images discussedpreviously, the postureized image of the teeth, along with thecolor/optical measurement data for the various regions of the teeth, maybe conveniently stored, maintained and accessed as part of the patientdental records. Such stored data may be utilized advantageously increating dental prosthesis that more correctly match the colors/regionsof adjacent teeth.

In a further refinement to the foregoing embodiment, computer 384preferably has included therein, or coupled thereto, a modem. With sucha modem capability (which may be hardware or software), computer 384 maycouple data to remote computer 386 over telecommunication channel 388.For example, remote computer 386 may be located at a dental laboratoryremotely located. Video images captured using intraoral camera 382 andcolor/optical data collected using intraoral reflectometer may betransmitted to a dental technician (for example) at the remote location,who may use such images and data to construct dental prosthesis.Additionally, computer 384 and remote computer 386 may be equipped withan internal or external video teleconference capability, therebyenabling a dentist and a dental technician or ceramist, etc., to have alive video or audio teleconference while viewing such images and/ordata.

For example, a live teleconference could take place, whereby the dentaltechnician or ceramist views video images captured using intraoralcamera 383, and after viewing images of the patient's teeth and facialfeatures and complexion, etc., instruct the dentist as to which areas ofthe patient's teeth are recommended for measurement using intraoralreflectometer 380. Such interaction between the dentist and dentaltechnician or ceramist may occur with or without postureization aspreviously described. Such interaction may be especially desirable at,for example, a try-in phase of a dental prosthesis, when minor changesor subtle characterizations may be needed in order to modify theprosthesis for optimum esthetic results.

A still further refinement may be understood with reference to FIG. 26.As illustrated in FIG. 26, color calibration chart 404 could be utilizedin combination with various elements of the previously describedembodiments, including intraoral camera 382. Color calibration chart 404may provide a chart of known color values, which may be employed, forexample, in the video image to further enhance correct skin tones ofpatient 402 in the displayed video image. As the patient's gingivaltissue, complexion and facial features, etc., may influence the finalesthetic results of a dental prosthesis, such a color calibration chartmay be desirably utilized to provide better esthetic results.

As an additional example, such a color calibration chart may be utilizedby computer 384 and/or 386 to “calibrate” the color data within acaptured image to true or known color values. For example, colorcalibration chart 404 may include one or more orientation markings 406,which may enable computers 384 and/or 386 to find and position colorcalibration chart 404 within a video frame. Thereafter, computers 384and/or 386 may then compare “known” color data values from colorcalibration chart (data indicative of the colors within colorcalibration chart 404 and their position relative to orientation mark ormarkings 406 are stored within computers 384 and/or 386, such as in alookup table, etc.) with the colors captured within the video image atpositions corresponding to the various colors of color calibration chart404. Based on such comparisons, computers 384 and/or 386 may coloradjust the video image in order to bring about a closer correspondencebetween the colors of the video image and known or true colors fromcolor calibration chart 404.

In certain embodiments, such color adjusted video data may be used inthe prosthesis preparation process, such as to color adjust the videoimage (whether or not postureized) in conjunction with color/opticaldata collected using intraoral reflectometer 380 (for example, asdescribed above or using data from intraoral reflectometer 380 tofurther color adjust portions of the video image), or to add subtlecharacterizations or modifications to a dental prosthesis, or to evenprepare a dental prosthesis, etc. While not believed to be as accurate,etc. as color/optical data collected using intraoral reflectometer 380,such color adjusted video data may be adequate in certain applications,environments, situations, etc., and such color adjusted video data maybe utilized in a similar manner to color data taken by a device such asintraoral reflectometer 380, including, for example, prosthesispreparation, patient data collection and storage, materials preparation,such as described elsewhere herein.

It should be further noted that color calibration chart 404 may bespecifically adapted (size, form and constituent materials, etc.) to bepositioned inside of the patient's mouth to be placed near the tooth orteeth being examined, so as to be subject to the same or nearly the sameambient lighting and environmental conditions, etc., as is the tooth orteeth being examined. It also should further be noted that theutilization of color calibration chart 404 to color correct video imagedata with a computer as provided herein also may be adapted to be usedin other fields, such as medical, industrial, etc., although its noveland advantageous use in the field of dentistry as described herein is ofparticular note and emphasis herein.

FIG. 27 illustrates a further embodiment of the present invention, inwhich an intraoral reflectometer in accordance with the presentinvention may be adapted to be mounted on, or removably affixed to, adental chair. An exemplary dental chair arrangement in accordance withthe present invention includes dental chair 410 is mounted on base 412,and may include typical accompaniments for such chairs, such as footcontrol 414, hose(s) 416 (for suction or water, etc.), sink and watersupply 420 and light 418. A preferably movable arm 422 extends out fromsupport 428 in order to provide a conveniently locatable support 430 onwhich various dental instruments 424 are mounted or affixed in aremovable manner. Tray 426 also may be included, on which a dentist mayposition other instruments or materials. In accordance with thisembodiment, however, instruments 424 include an intraoral reflectometerin accordance with the present invention, which is convenientlypositioned and removably mounted/affixed on support 430, so thatcolor/optical measurements, data collection and storage and prosthesispreparation may be conveniently carried out by the dentist. As opposedto large and bulky prior art instruments, the present invention enablesan intraoral reflectometer for collecting color/optical data, in someembodiments combined or utilized with an intraoral camera as describedelsewhere herein, which may be readily adapted to be positioned in aconvenient location on a dental chair. Such a dental chair also may bereadily adapted to hold other instruments, such as intraoral cameras,drills, lights, etc.

Additionally, and to emphasize the wide utility and variability ofvarious of the inventive concepts and techniques disclosed herein, itshould be apparent to those skilled in the art in view of thedisclosures herein that the apparatus and methodology may be utilized tomeasure the optical properties of objects/teeth using other opticalfocusing and gathering elements, in addition to the fiber opticsemployed in preferred embodiments herein. For example, lenses or mirrorsor other optical elements may also be utilized to construct both thelight source element and the light receiver element. A flashlight orother commonly available light source, as particular examples, may beutilized as the light source element, and a common telescope with aphotoreceiver may be utilized as the receiver element in a large scaleembodiment of the invention. Such refinements utilizing teachingsprovided herein are expressly within the scope of the present invention.

As will be apparent to those skilled in the art, certain refinements maybe made in accordance with the present invention. For example, a centrallight source fiber optic is utilized in certain preferred embodiments,but other light source arrangements (such as a plurality of light sourcefibers, etc.). In addition, lookup tables are utilized for variousaspects of the present invention, but polynomial type calculations couldsimilarly be employed. Thus, although various preferred embodiments ofthe present invention have been disclosed for illustrative purposes,those skilled in the art will appreciate that various modifications,additions and/or substitutions are possible without departing from thescope and spirit of the present invention as disclosed in the claims.

Reference is also made to copending international application filed oneven date herewith under the Patent Cooperation Treaty, for “Apparatusand Method for Measuring Optical Characteristics of an Object,” by theinventors hereof, which is hereby incorporated by reference.

What is claimed is:
 1. A method, comprising the steps of: positioning aprobe in proximity to a dental object, wherein the probe provides lightto the object and receives light from the object, wherein the receivedlight is coupled to a video camera, wherein the camera has a field ofview, wherein the object is positioned in the field of view of thecamera; generating optical characteristics data indicative of theoptical characteristics including at least color characteristics of theobject, wherein the optical characteristics data are generated based oncamera data corresponding to the object and based on camera datacorresponding to a color calibration standard generated with the colorcalibration standard in the field of view of the camera, wherein thecolor calibration standard includes one or more visible features,wherein the camera data corresponding to the color calibration standardinclude camera data from one or more regions of the color calibrationstandard that are a predetermined position with respect to the one ormore visible features; and storing the optical characteristics data in arecord of a software database, wherein the software database includes aplurality of database records.
 2. The method of claim 1, wherein thecalibration standard and the object are simultaneously in the field ofview of the camera.
 3. The method of claim 1, wherein the dental objectcorresponds to a patient, wherein the calibration standard is locatednear the dental object.
 4. The method of claim 3, wherein thecalibration standard is positioned in the mouth of the patient.
 5. Themethod of claim 1, wherein data from the camera corresponding to theobject are adjusted based on data from the camera corresponding to thecalibration standard.
 6. The method of claim 5, wherein the data fromthe camera corresponding to the object are color adjusted.
 7. The methodof claim 1, wherein the optical characteristics data are generated aplurality of times for a plurality of dental objects to generate aplurality of optical characteristics database records.
 8. The method ofclaim 7, wherein the database records are associated with particularpatients.
 9. The method of claim 7, wherein the database records storepictures of the dental objects.
 10. The method of claim 1, wherein theoptical characteristics data are generated a plurality of times for thedental object, wherein the database stores a historical record of theoptical characteristics of the dental object.
 11. The method of claim 1,wherein a second dental object is produced based on the opticalcharacteristics data.
 12. The method of claim 11, wherein the seconddental object comprises a denture.
 13. The method of claim 11, whereinthe second dental object comprises a dental prosthesis.
 14. The methodof claim 11, wherein the second dental object comprises a filling. 15.The method of claim 11, wherein the second dental object comprises atooth-colored filling.
 16. The method of claim 11, wherein the seconddental object comprises a composite filling.
 17. The method of claim 11,wherein the second dental object is produced based on a porcelain recipedetermined in accordance with the optical characteristics data.
 18. Themethod of claim 1, wherein the optical characteristics data areelectronically transmitted to a remote location, wherein a second objectis produced at the remote location based on the transmitted opticalcharacteristics data.
 19. The method of claim 18, wherein the electronictransmission comprises a modem transmission.
 20. The method of claim 18,wherein the electronic transmission includes a transmission of a pictureof the dental object.
 21. The method of claim 1, wherein the probe has aremovable cover element.
 22. The method of claim 21, wherein theremovable cover element comprises a shield.
 23. The method of claim 21,wherein the removable cover element is positioned on the probe prior topositioning of the probe in proximity to the dental object.
 24. Themethod of claim 23, wherein the removable cover element is sterilizedprior to being positioned on the probe.
 25. The method of claim 1,wherein the database includes date and time information associated withthe optical characteristics data.
 26. The method of claim 25, whereinthe software database stores sectoring information with the opticalcharacteristics data.
 27. The method of claim 25, wherein the softwaredatabase stores information corresponding to a pictorial representationof the dental object that includes sector grid lines.
 28. The method ofclaim 1, wherein the dental object is sectored into a plurality ofsectors, wherein optical characteristics data indicative of the opticalcharacteristics are generated a plurality of times, including at leastonce for each of the plurality of sectors.
 29. The method of claim 1,wherein a material mixing unit receives the optical characteristicsdata, wherein the material mixing unit prepares constituent materialsfor a second object based on the optical characteristics data.
 30. Amethod of producing a second dental object, comprising the steps of:positioning a probe in proximity to a first dental object, wherein theprobe provides light to the first dental object and receives light fromthe first dental object, wherein the received light is coupled to avideo camera, wherein the camera has a field of view, wherein the firstdental object is positioned in the field of view of the camera, whereinoptical characteristics data including at least color data are generatedbased on camera data corresponding to the first dental object and basedon camera data corresponding to a color calibration standard generatedwith the color calibration standard in the field of view of the camera,wherein the color calibration standard includes one or more visiblefeatures, wherein the camera data corresponding to the color calibrationstandard include camera data from one or more reunions of the colorcalibration standard that are a predetermined position with respect tothe one or more visible features; transmitting the opticalcharacteristics data to a remote location; receiving the opticalcharacteristics data at the remote location; and producing the seconddental object based on the optical characteristics data.
 31. The methodof claim 30, wherein the calibration standard and the first dentalobject are simultaneously in the field of view of the camera.
 32. Themethod of claim 30, wherein the first dental object comprises a dentalobject of a patient, wherein the calibration standard is located nearthe first dental object.
 33. The method of claim 32, wherein thecalibration standard is positioned in the mouth of the patient.
 34. Themethod of claim 30, wherein data from the camera corresponding to thefirst dental object are adjusted based on data from the cameracorresponding to the calibration standard.
 35. The method of claim 34,wherein the data from the camera corresponding to the first dentalobject are color adjusted.
 36. The method of claim 30, wherein thetransmission and receipt of the optical characteristics data comprises amodem transmission.
 37. The method of claim 30, wherein the transmissionand receipt of the optical characteristics data comprises a facsimiletransmission.
 38. The method of claim 30, wherein the electronictransmission includes a transmission of a picture of the first dentalobject.
 39. The method of claim 30, further comprising the step ofgenerating second optical characteristics data by positioning a secondprobe in proximity to the second dental object.
 40. The method of claim39, further comprising the step of comparing the first opticalcharacteristics data with the second optical characteristics data. 41.The method of claim 39, wherein the second probe comprises a probelocated at the remote location.
 42. The method of claim 39, wherein thesecond probe is the same probe that was positioned in proximity to thefirst dental object.
 43. The method of claim 30, wherein a materialmixing unit receives the optical characteristics data, wherein thematerial mixing unit prepares constituent materials for the seconddental object based on the optical characteristics data.
 44. The methodof claim 30, wherein the probe is handheld.
 45. The method of claim 30,wherein the probe has a removable cover element.
 46. The method of claim45, wherein the removable cover element comprises a shield.
 47. Themethod of claim 45, wherein the removable cover element is positioned onthe probe prior to positioning of the probe in proximity to the firstdental object.
 48. The method of claim 47, wherein the removable coverelement is sterilized prior to being positioned on the probe.
 49. Themethod of claim 30, wherein the probe is positioned in proximity to thefirst dental object by relative movement of the probe with respect tothe first dental object.
 50. A method of determining the opticalcharacteristics of a dental object, comprising the steps of: positioninga probe in proximity to the object, wherein the probe provides light tothe object and receives light from the object, wherein the receivedlight is coupled to a video camera, wherein the camera has a field ofview, wherein the object is positioned in the field of view of thecamera; and generating optical characteristics data indicative of theoptical characteristics of the object including at least colorcharacteristics, wherein the optical characteristics data are generatedbased on camera data corresponding to the object and camera datacorresponding to a color calibration standard generated with the colorcalibration standard in the field of view of the camera, wherein thecolor calibration standard includes one or more visible features,wherein the camera data corresponding to the color calibration standardinclude camera data from one or more regions of the color calibrationstandard that are a predetermined position with respect to the one ormore visible features.
 51. The method of claim 50, wherein thecalibration standard and the first dental object are simultaneously inthe field of view of the camera.
 52. The method of claim 50, wherein thedental object corresponds to a patient, wherein the calibration standardis located near the dental object.
 53. The method of claim 52, whereinthe calibration standard is positioned in the mouth of the patient. 54.The method of claim 50, wherein data from the camera corresponding tothe first dental object are adjusted based on data from the cameracorresponding to the calibration standard.
 55. The method of claim 54,wherein the data from the camera corresponding to the dental object arecolor adjusted.
 56. The method of claim 50, wherein the opticalcharacteristics data are stored in a database, wherein the opticalcharacteristics data are generated a plurality of times for a pluralityof dental objects to generate a plurality of optical characteristicsdatabase records.
 57. The method of claim 56, wherein the databaserecords are associated with particular patients.
 58. The method of claim56, wherein the database records store pictures of the dental objects.59. The method of claim 50, wherein the optical characteristics data aregenerated a plurality of times for the dental object, wherein a databasestores a historical record of the optical characteristics of the dentalobject.
 60. The method of claim 50, wherein a second dental object isproduced based on the optical characteristics data.
 61. The method ofclaim 60, wherein the second dental object comprises a denture.
 62. Themethod of claim 60, wherein the second dental object comprises a dentalprosthesis.
 63. The method of claim 60, wherein the second dental objectcomprises a filling.
 64. The method of claim 60, wherein the seconddental object comprises a tooth-colored filling.
 65. The method of claim60, wherein the second dental object comprises a composite filling. 66.The method of claim 60, wherein the second dental object is producedbased on a porcelain recipe determined in accordance with the opticalcharacteristics data.
 67. The method of claim 50, wherein the opticalcharacteristics data are electronically transmitted to a remotelocation, wherein a second object is produced at the remote locationbased on the transmitted optical characteristics data.
 68. The method ofclaim 67, wherein the electronic transmission comprises a modemtransmission.
 69. The method of claim 67, wherein the electronictransmission includes a transmission of a picture of the dental object.70. The method of claim 50, wherein the probe has a removable coverelement.
 71. The method of claim 70, wherein the removable cover elementcomprises a shield.
 72. The method of claim 70, wherein the removablecover element is positioned on the probe prior to positioning of theprobe in proximity to the dental object.
 73. The method of claim 72,wherein the removable cover element is sterilized prior to beingpositioned on the probe.
 74. The method of claim 50, wherein the opticalcharacteristics data are stored in a database, wherein the databaseincludes date and time information associated with the opticalcharacteristics data.
 75. The method of claim 50, wherein the opticalcharacteristics data are stored in a database, wherein the dental objectis sectored into a plurality of sectors, wherein optical characteristicsdata indicative of the optical characteristics are generated a pluralityof times, including at least once for each of the plurality of sectors.76. The method of claim 75, wherein the software database storessectoring information with the optical characteristics data.
 77. Themethod of claim 75, wherein the software database stores informationcorresponding to a pictorial representation of the dental object thatincludes sector grid lines.
 78. The method of claim 50, wherein amaterial mixing unit receives the optical characteristics data, whereinthe material mixing unit prepares constituent materials for a secondobject based on the optical characteristics data.
 79. A method,comprising the steps of: positioning a probe in proximity to a dentalobject, wherein the probe provides light to the dental object andreceives light from the dental object, wherein the received light iscoupled to a camera, wherein the camera has a field of view, wherein thedental object is positioned in the field of view of the camera;generating optical characteristics data indicative of the opticalcharacteristics of the dental object, wherein the opticalcharacteristics data are generated based on camera data corresponding tothe dental object and based on camera data corresponding to acalibration standard, wherein the calibration standard and the dentalobject are simultaneously in the field of view of the camera; andstoring the optical characteristics data in a record of a softwaredatabase, wherein the software database includes a plurality of databaserecords.
 80. The method of claim 79, wherein the dental objectcorresponds to a patient, wherein the calibration standard is locatednear the dental object.
 81. The method of claim 80, wherein thecalibration standard is positioned in the mouth of the patient.
 82. Themethod of claim 79, wherein data from the camera corresponding to thedental object are adjusted based on data from the camera correspondingto the calibration standard.
 83. The method of claim 82, wherein thedata from the camera corresponding to the dental object are coloradjusted.
 84. The method of claim 79, wherein the opticalcharacteristics data are generated a plurality of times for a pluralityof dental objects to generate a plurality of optical characteristicsdatabase records.
 85. The method of claim 84, wherein the databaserecords are associated with particular patients.
 86. The method of claim84, wherein the database records store pictures of the dental objects.87. The method of claim 79, wherein the optical characteristics data aregenerated a plurality of times for the dental object, wherein thedatabase stores a historical record of the optical characteristics ofthe dental object.
 88. The method of claim 79, wherein a second dentalobject is produced based on the optical characteristics data.
 89. Themethod of claim 88, wherein the second dental object comprises adenture.
 90. The method of claim 88, wherein the second dental objectcomprises a dental prosthesis.
 91. The method of claim 88, wherein thesecond dental object comprises a filling.
 92. The method of claim 88,wherein the second dental object comprises a tooth-colored filling. 93.The method of claim 88, wherein the second dental object comprises acomposite filling.
 94. The method of claim 88, wherein the second dentalobject is produced based on a porcelain recipe determined in accordancewith the optical characteristics data.
 95. The method of claim 79,wherein the optical characteristics data are electronically transmittedto a remote location, wherein a second dental object is produced at theremote location based on the transmitted optical characteristics data.96. The method of claim 95, wherein the electronic transmissioncomprises a modern transmission.
 97. The method of claim 95, wherein theelectronic transmission includes a transmission of a picture of thedental object.
 98. The method of claim 79, wherein the probe has aremovable cover element.
 99. The method of claim 98, wherein theremovable cover element comprises a shield.
 100. The method of claim 98,wherein the removable cover element is positioned on the probe prior topositioning of the probe in proximity to the dental object.
 101. Themethod of claim 100, wherein the removable cover element is sterilizedprior to being positioned on the probe.
 102. The method of claim 79,wherein the database includes date and time information associated withthe optical characteristics data.
 103. The method of claim 79, whereinthe dental object is sectored into a plurality of sectors, whereinoptical characteristics data indicative of the optical characteristicsare generated a plurality of times, including at least once for each ofthe plurality of sectors.
 104. The method of claim 103, wherein thesoftware database stores sectoring information with the opticalcharacteristics data.
 105. The method of claim 104, wherein the softwaredatabase stores information corresponding to a pictorial representationof the dental object that includes sector grid lines.
 106. The method ofclaim 79, wherein a material mixing unit receives the opticalcharacteristics data, wherein the material mixing unit preparesconstituent materials for a second dental object based on the opticalcharacteristics data.
 107. A method of producing a second dental object,comprising the steps of: positioning a probe in proximity to a firstdental object, wherein the probe provides light to the object aidreceives light from the first dental object, wherein the received lightis coupled to a camera, wherein the camera has a field of view, whereinthe first dental object is positioned in the field of view of thecamera, wherein the optical characteristics data are generated based oncamera data corresponding to the first dental object and based on cameradata corresponding to a calibration standard, wherein the calibrationstandard and the object are simultaneously in the field of view of thecamera; transmitting the optical characteristics data to a remotelocation; receiving the optical characteristics data at the remotelocation; and producing the second dental object based on the opticalcharacteristics data.
 108. The method of claim 107, wherein the firstdental object corresponds to a patient, wherein the calibration standardis located near the first dental object.
 109. The method of claim 108,wherein the calibration standard is positioned in the mouth of thepatient.
 110. The method of claim 107, wherein data from the cameracorresponding to the first dental object are adjusted based on data fromthe camera corresponding to the calibration standard.
 111. The method ofclaim 110, wherein the data from the camera corresponding to the firstdental object are color adjusted.
 112. The method of claim 107, whereinthe transmission and receipt of the optical characteristics datacomprises a modem transmission.
 113. The method of claim 107, whereinthe transmission and receipt of the optical characteristics datacomprises a facsimile transmission.
 114. The method of claim 107,wherein the electronic transmission includes a transmission of a pictureof the first dental object.
 115. The method of claim 107, furthercomprising the step of generating second optical characteristics data bypositioning a second probe in proximity to the second dental object.116. The method of claim 115, further comprising the step of comparingthe first optical characteristics data with the second opticalcharacteristics data.
 117. The method of claim 115, wherein the secondprobe comprises a probe located at the remote location.
 118. The methodof claim 115, wherein the second probe is the same probe that waspositioned in proximity to the first dental object.
 119. The method ofclaim 107, wherein a material mixing unit receives the opticalcharacteristics data, wherein the material mixing unit preparesconstituent materials for the second dental object based on the opticalcharacteristics data.
 120. The method of claim 107, wherein the probe ishandheld.
 121. The method of claim 107, wherein the probe has aremovable cover element.
 122. The method of claim 121, wherein theremovable cover element comprises a shield.
 123. The method of claim121, wherein the removable cover element is positioned on the probeprior to positioning of the probe in proximity to the first dentalobject.
 124. The method of claim 123, wherein the removable coverelement is sterilized prior to being positioned on the probe.
 125. Themethod of claim 107, wherein the probe is positioned in proximity to thefirst dental object by relative movement of the probe with respect tothe first dental object.
 126. A method of determining the opticalcharacteristics of a dental object, comprising the steps of: positioninga probe in proximity to the object, wherein the probe provides light tothe dental object and receives light from the dental object, wherein thereceived light is coupled to a camera, wherein the camera has a field ofview, wherein the dental object is positioned in the field of view ofthe camera; and generating optical characteristics data indicative ofthe optical characteristics of the dental object, wherein the opticalcharacteristics data are generated based on camera data corresponding tothe dental object and camera data corresponding to a calibrationstandard, wherein the calibration standard and the dental object aresimultaneously in the field of view of the camera.
 127. The method ofclaim 126, wherein the dental object corresponds to a patient, whereinthe calibration standard is located near the dental object.
 128. Themethod of claim 127, wherein the calibration standard is positioned inthe mouth of the patient.
 129. The method of claim 126, wherein datafrom the camera corresponding to the dental object are adjusted based ondata from the camera corresponding to the calibration standard.
 130. Themethod of claim 129, wherein the data from the camera corresponding tothe dental object are color adjusted.
 131. The method of claim 126,wherein the optical characteristics data are stored in a database,wherein the optical characteristics data are generated a plurality oftimes for a plurality of dental objects to generate a plurality ofoptical characteristics database records.
 132. The method of claim 131,wherein the database records are associated with particular patients.133. The method of claim 131, wherein the database records storepictures of the dental objects.
 134. The method of claim 131, whereinthe optical characteristics data are generated a plurality of times forthe dental object, wherein a database stores a historical record of theoptical characteristics of the dental object.
 135. The method of claim126, wherein a second dental object is produced based on the opticalcharacteristics data.
 136. The method of claim 135, wherein the seconddental object comprises a denture.
 137. The method of claim 135, whereinthe second dental object comprises a dental prosthesis.
 138. The methodof claim 135, wherein the second dental object comprises a filling. 139.The method of claim 135, wherein the second dental object comprises atooth-colored filling.
 140. The method of claim 135, wherein the seconddental object comprises a composite filling.
 141. The method of claim135, wherein the second dental object is produced based on a porcelainrecipe determined in accordance with the optical characteristics data.142. The method of claim 126, wherein the optical characteristics dataare electronically transmitted to a remote location, wherein a secondobject is produced at the remote location based on the transmittedoptical characteristics data.
 143. The method of claim 142, wherein theelectronic transmission comprises a modem transmission.
 144. The methodof claim 142, wherein the electronic transmission includes atransmission of a picture of the dental object.
 145. The method of claim126, wherein the probe has a removable cover element.
 146. The method ofclaim 145, wherein the removable cover element comprises a shield. 147.The method of claim 145, wherein the removable cover element ispositioned on the probe prior to positioning of the probe in proximityto the dental object.
 148. The method of claim 147, wherein theremovable cover element is sterilized prior to being positioned on theprobe.
 149. The method of claim 126, wherein the optical characteristicsdata are stored in a database, wherein the database includes date andtime information associated with the optical characteristics data. 150.The method of claim 126, wherein the optical characteristics data arestored in a database, wherein the dental object is sectored into aplurality of sectors, wherein optical characteristics data indicative ofthe optical characteristics are generated a plurality of times,including at least once for each of the plurality of sectors.
 151. Themethod of claim 150, wherein the software database stores sectoringinformation with the optical characteristics data.
 152. The method ofclaim 150, wherein the software database stores informationcorresponding to a pictorial representation of the tooth that includessector grid lines.
 153. The method of claim 126, wherein a materialmixing unit receives the optical characteristics data, wherein thematerial mixing unit prepares constituent materials for a second dentalobject based on the optical characteristics data.
 154. A method ofproducing a second dental object, comprising the steps of: positioning aprobe in proximity to a first dental object, wherein the probe provideslight to the first dental object and receives light from the firstdental object, wherein the received light is coupled to a camera,wherein the camera has a field of view, wherein the first dental objectis positioned in the field of view of the camera, wherein the opticalcharacteristics data are generated based on camera data corresponding tothe first dental object and based on camera data corresponding to acalibration standard; transmitting the optical characteristics data to aremote location; receiving the optical characteristics data at theremote location; and producing the second dental object based on theoptical characteristics data, wherein a material mixing unit receivesthe optical characteristics data, wherein the material mixing unitprepares constituent materials for the second dental object based on theoptical characteristics data.
 155. The method of claim 154, wherein thecalibration standard and the first dental object are simultaneously inthe field of view of the camera.
 156. The method of claim 154, whereinthe first dental object corresponds to a patient, wherein thecalibration standard is located near the first dental object.
 157. Themethod of claim 156, wherein the calibration standard is positioned inthe mouth of the patient.
 158. The method of claim 154, wherein datafrom the camera corresponding to the first dental object are adjustedbased on data from the camera corresponding to the calibration standard.159. The method of claim 158, wherein the data from the cameracorresponding to the first dental object are color adjusted.
 160. Themethod of claim 154, wherein the transmission and receipt of the opticalcharacteristics data comprises a modem transmission.
 161. The method ofclaim 154, wherein the transmission and receipt of the opticalcharacteristics data comprises a facsimile transmission.
 162. The methodof claim 154, wherein the electronic transmission includes atransmission of a picture of the first dental object.
 163. The method ofclaim 154, further comprising the step of generating second opticalcharacteristics data by positioning a second probe in proximity to thesecond dental object.
 164. The method of claim 163, further comprisingthe step of comparing the first optical characteristics data with thesecond optical characteristics data.
 165. The method of claim 163,wherein the second probe comprises a probe located at the remotelocation.
 166. The method of claim 163, wherein the second probe is thesame probe that was positioned in proximity to the first dental object.167. The method of claim 154, wherein the probe is handhold.
 168. Themethod of claim 154, wherein the probe has a removable cover element.169. The method of claim 168, wherein the removable cover elementcomprises a shield.
 170. The method of claim 168, wherein the removablecover element is positioned on the probe prior to positioning of theprobe in proximity to the first dental object.
 171. The method of claim170, wherein the removable cover element is sterilized prior to beingpositioned on the probe.
 172. The method of claim 154, wherein the probeis positioned in proximity to the firs dental object by relativemovement of the probe with respect to the first dental object.
 173. Amethod of determining the optical characteristics of a dental object,comprising the steps of: providing light to the dental object andreceiving light from the dental object, wherein the received light iscoupled to a camera, wherein the camera has a field of view, wherein thedental object is positioned in the field of view of the camera; andgenerating optical characteristics data indicative of the opticalcharacteristics of the dental object, wherein the opticalcharacteristics data are generated based on camera data corresponding tothe dental object and camera data corresponding to a calibrationstandard, wherein the calibration standard and the dental object aresimultaneously in the field of view of the camera.
 174. The method ofclaim 173, wherein the dental object corresponds to a patient, whereinthe calibration standard is located near the dental object.
 175. Themethod of claim 174, wherein the calibration standard is positioned inthe mouth of the patient.
 176. The method of claim 173, wherein datafrom the camera corresponding to the dental object are adjusted based ondata from the camera corresponding to the calibration standard.
 177. Themethod of claim 176, wherein the data from the camera corresponding tothe dental object are color adjusted.
 178. The method of claim 173,wherein the optical characteristics data are stored in a database,wherein the optical characteristics data are generated a plurality oftimes for a plurality of dental objects to generate a plurality ofoptical characteristics database records.
 179. The method of claim 178,wherein the database records are associated with particular patients.180. The method of claim 178, wherein the database records storepictures of the dental objects.
 181. The method of claim 178, whereinthe optical characteristics data are generated a plurality of times forthe dental object, wherein a database stores a historical record of theoptical characteristics of the dental object.
 182. The method of claim173, wherein a second dental object is produced based on the opticalcharacteristics data.
 183. The method of claim 182, wherein the seconddental object comprises a denture.
 184. The method of claim 182, whereinthe second dental object comprises a dental prosthesis.
 185. The methodof claim 182, wherein the second dental object comprises a filling. 186.The method of claim 182, wherein the second dental object comprises atooth-colored filling.
 187. The method of claim 182, wherein the seconddental object comprises a composite filling.
 188. The method of claim182, wherein the second dental object is produced based on a porcelainrecipe determined in accordance with the optical characteristics data.189. The method of claim 173, wherein the optical characteristics dataare electronically transmitted to a remote location, wherein a secondobject is produced at the remote location based on the transmittedoptical characteristics data.
 190. The method of claim 189, wherein theelectronic transmission comprises a modem transmission.
 191. The methodof claim 189, wherein the electronic transmission includes atransmission of a picture of the dental object.
 192. The method of claim173, wherein the light is provided and received via a probe, wherein theprobe has a removable cover element.
 193. The method of claim 192,wherein the removable cover element comprises a shield.
 194. The methodof claim 192, wherein the removable cover element is positioned on theprobe prior to positioning of the probe in proximity to the dentalobject.
 195. The method of claim 194, wherein the removable coverelement is sterilized prior to being positioned on the probe.
 196. Themethod of claim 173, wherein the optical characteristics data are storedin a database, wherein the database includes date and time informationassociated with the optical characteristics data.
 197. The method ofclaim 173, wherein the optical characteristics data are stored in adatabase, wherein the dental object is sectored into a plurality ofsectors, wherein optical characteristics data indicative of the opticalcharacteristics are generated a plurality of times, including at leastonce for each of the plurality of sectors.
 198. The method of claim 197,wherein the software database stores sectoring information with theoptical characteristics data.
 199. The method of claim 197, wherein thesoftware database stores information corresponding to a pictorialrepresentation of the dental object that includes sector grid lines.200. The method of claim 173, wherein a material mixing unit receivesthe optical characteristics data, wherein the material mixing unitprepares constituent materials for a second dental object based on theoptical characteristics data.
 201. The method of claims 79, 107, 126,154 or 173, wherein the camera comprises an intraoral camera.
 202. Themethod of claims 79, 107, 126, 154 or 173, wherein the camera comprisesa video camera.